June 14, 2021 — Toronto, Ontario — Greenbrook TMS Inc. (TSX: GTMS, NASDAQ: GBNH) (“Greenbrook” or the “Company”) today announced that it has completed a non-brokered private placement (the “Private Placement”) of common shares of the Company (the “Common Shares”). Pursuant to the Private Placement, an aggregate of 2,353,347 Common Shares were issued at a price of US$10.00 per share, for aggregate gross proceeds to the Company of approximately US$23.5 million. The financing was led by new investor Masters Special Situations, LLC and affiliates thereof (“MSS”). In connection with the Private Placement, MSS will receive the right to appoint a nominee to the board of directors of the Company. Additional new investors, including BioStar Capital, also participated in the financing, along with existing investors, Greybrook Health Inc. (“Greybrook Health”) and 1315 Capital II, L.P. (“1315 Capital”).

The Company intends to use the proceeds from the Private Placement for the development of new mental health service centers that specialize in Transcranial Magnetic Stimulation (“TMS”) treatment as well as working capital and general corporate purposes.

The offer and sale of the Common Shares in the Private Placement was made in the United States solely to accredited investors pursuant to the exemption from registration in Rule 506(c) of Regulation D promulgated by the United States Securities and Exchange Commission (the “SEC”) under the United States Securities Act of 1933, as amended (the “Securities Act”) and in Canada pursuant to and in compliance with exemptions from the prospectus requirements of applicable Canadian securities laws.

In connection with the Private Placement, MSS, Greybrook Health and 1315 Capital will each receive the right to appoint a nominee to the board of directors of the Company, and all investors will receive customary registration rights.

This press release does not constitute an offer to sell or the solicitation of an offer to buy any securities in any jurisdiction in which such offer, solicitation or sale would be unlawful.

MI 61-101 Disclosure

Greybrook Health and 1315 Capital are each insiders of the Company. Accordingly, the Private Placement is considered a “related party transaction” for purposes of Multilateral Instrument 61-101 – Protection of Minority Security Holders in Special Transactions (“MI 61-101”). Pursuant to MI 61-101, the Company will file a material change report providing disclosure in relation to each “related party transaction” on SEDAR under the Company’s issuer profile at www.sedar.com. The Company did not file the material change report more than 21 days before the expected closing date of the Private Placement as the details of the Private Placement and the participation therein by the “related parties” of the Company were not settled until shortly prior to the closing of the Private Placement, and the Company wished to close the Private Placement on an expedited basis for business reasons.

The Company is relying on exemptions from the formal valuation and minority shareholder approval requirements available under MI 61-101. The Company is exempt from the formal valuation requirement in section 5.4 of MI 61- 101 in reliance on section 5.5(a) of MI 61-101 as the fair market value of the transaction, insofar as it involves interested parties, is not more than 25% of the Company’s market capitalization. Additionally, the Company is exempt from the minority shareholder approval requirement in section 5.6 of MI 61-101 in reliance on section 5.7(1)(a) as the fair market value of the transaction, insofar as it involves interested parties, is not more than 25% of the Company’s market capitalization.

About Greenbrook TMS Inc.

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Operating through 128 Company-operated treatment centers, Greenbrook is a leading provider of TMS therapy, an FDA-cleared, non-invasive therapy for the treatment of Major Depressive Disorder and other mental health disorders, in the United States. TMS therapy provides local electromagnetic stimulation to specific brain regions known to be directly associated with mood regulation. Greenbrook has provided more than 620,000 TMS treatments to over 17,000 patients struggling with depression.

About Masters Special Situations, LLC

MSS is an affiliate of Masters Capital Management, LLC, an SEC registered investment adviser based in Atlanta, Georgia. MSS invests growth capital in innovative, small cap public companies in North America.

Cautionary Note Regarding Forward-Looking Information

Certain information in this press release, including with respect to the Private Placement, including the anticipated use of proceeds thereof, constitutes forward-looking information within the meaning of applicable securities laws in Canada and the United States, including the United States Private Securities Litigation Reform Act of 1995. In some cases, but not necessarily in all cases, forward-looking information can be identified by the use of forward-looking terminology such as “plans”, “targets”, “expects” or “does not expect”, “is expected”, “an opportunity exists”, “is positioned”, “estimates”, “intends”, “assumes”, “anticipates” or “does not anticipate” or “believes”, or variations of such words and phrases or state that certain actions, events or results “may”, “could”, “would”, “might”, “will” or “will be taken”, “occur” or “be achieved”. In addition, any statements that refer to expectations, projections or other characterizations of future events or circumstances contain forward-looking information. Statements containing forward-looking information are not historical facts but instead represent management’s expectations, estimates and projections regarding future events.

Forward-looking information is necessarily based on a number of opinions, assumptions and estimates that, while considered reasonable by the Company as of the date of this press release, are subject to known and unknown risks, uncertainties, assumptions and other factors that may cause the actual results, level of activity, performance or achievements to be materially different from those expressed or implied by such forward-looking information, including but not limited to the factors described in greater detail in the “Risk Factors” section of the Company’s current annual information form and in the Company’s other materials filed with the Canadian securities regulatory authorities and the SEC from time to time, available at www.sedar.com and www.sec.gov, respectively. These factors are not intended to represent a complete list of the factors that could affect the Company; however, these factors should be considered carefully. There can be no assurance that such estimates and assumptions will prove to be correct. The forward-looking statements contained in this press release are made as of the date of this press release, and the Company expressly disclaims any obligation to update or alter statements containing any forward-looking information, or the factors or assumptions underlying them, whether as a result of new information, future events or otherwise, except as required by law.

Contacts

Glen Akselrod Investor Relations Greenbrook TMS Inc.

Email: investorrelations@greenbrooktms.com Phone: 1-855-797-4867

June 14, 2021 – Toronto, ON – Greenbrook TMS Inc. (TSX: GTMS, NASDAQ: GBNH) (“Greenbrook” or the “Company”), a leading provider of Transcranial Magnetic Stimulation (“TMS”) therapy in the United States, announced today the results of voting at its annual and special meeting of shareholders held earlier today (the “Meeting”). Each of the matters voted upon at the Meeting as set out below is described in greater detail in the Notice of Annual and Special Meeting of Shareholders and Management Information Circular of Greenbrook dated May 7, 2021 (the “Circular”).

The total number of common shares represented by holders by proxy at the Meeting was 8,276,984, representing approximately 60.26% of Greenbrook’s outstanding common shares entitled to be voted.

Election of Directors

All of the nominees listed in the Management Information Circular of Greenbrook prepared in connection with the Meeting were elected as directors by a resolution passed by a majority of the shareholders represented by proxy at the Meeting, to hold office until the next annual meeting following their election or until their successors are elected or appointed. The following represents the votes received with regard to such matter:

Appointment of Auditors

KPMG LLP was reappointed as auditor of Greenbrook and the directors were authorized to fix the auditor’s remuneration by a resolution passed by a majority of the shareholders represented by proxy at the Meeting. The following represents the votes received with regard to such matter:

Amendments to the Stock Option Plan

Certain amendments to Greenbrook’s amended and restated stock option plan were approved. The following represents the votes received with regard to such matter:

Approval of Unallocated Options and Share-Based Awards

All unallocated Options and Share-Based Awards (as defined in the Circular) under Greenbrook’s amended and restated omnibus equity incentive plan were approved. The following represents the votes received with regard to such matter:

About Greenbrook TMS Inc.

Operating through 128 Company-operated treatment centers, Greenbrook is a leading provider of TMS therapy, an FDA-cleared, non-invasive therapy for the treatment of Major Depressive Disorder and other mental health disorders, in the United States. TMS therapy provides local electromagnetic stimulation to specific brain regions known to be directly associated with mood regulation. Greenbrook has provided more than 620,000 TMS treatments to over 17,000 patients struggling with depression.

For further information please contact:

Glen Akselrod Investor Relations Greenbrook TMS Inc.

Contact Information: investorrelations@greenbrooktms.com 1-855-797-4867

Toronto, Canada – May 13, 2021 – Greenbrook TMS Inc. (TSX: GTMS) (NASDAQ: GBNH) (“Greenbrook” or the “Company”) today announced that, due to market conditions, pricing for its previously-announced equity offering (the “Offering”) will be temporarily delayed.

This press release does not constitute an offer to sell or the solicitation of an offer to buy securities, nor will there be any sale of the securities in any province, state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such province, state or jurisdiction. The Company has filed a short form base PREP prospectus (the “Prospectus”) in Canada and a registration statement (including a prospectus) on Form F-10 (the “Registration Statement”) with the U.S. Securities and Exchange Commission (the “SEC”), to which the Offering relates. The Company expects to amend the Prospectus and the Registration Statement prior to the Offering. Accordingly, these securities may not be sold, nor may offers to buy be accepted, prior to the time the amended Prospectus is filed in Canada and the Registration Statement (as amended) becomes effective. Before you invest, you should read the prospectus in that Registration Statement and the other documents the Company has filed with the SEC for more complete information about the Company and the Offering to which this communication relates. You may obtain these documents for free by visiting EDGAR on the SEC’s website at www.sec.gov or by contacting the offices of Stifel, Nicolaus & Company, Incorporated Attention: Syndicate, One Montgomery Street, Suite 3700, San Francisco, CA 94104, by telephone at (415) 364-2720, or by email at syndprospectus@stifel.com. Prospective Canadian investors may obtain a copy of the Canadian Prospectus from Stifel Nicolaus Canada Inc. care of the Stifel, Nicolaus & Company, Incorporated details referred to above. Prospective Canadian investors should clearly indicate in their request that they are a Canadian prospective investor and are requesting a copy of the Canadian Prospectus. The securities to be offered in the Offering have not been nor will be approved or disapproved by any regulatory authority, nor has any such authority passed upon, nor will pass upon, the accuracy or adequacy of the Prospectus or the Registration Statement.

About Greenbrook TMS Inc.

Operating through 128 Company-operated treatment centers, Greenbrook is a leading provider of Transcranial Magnetic Stimulation (“TMS”) therapy, an FDA-cleared, non-invasive therapy for the treatment of Major Depressive Disorder and other mental health disorders, in the United States. TMS therapy provides local electromagnetic stimulation to specific brain regions known to be directly associated with mood regulation. Greenbrook has provided more than 620,000 TMS treatments to over 17,000 patients struggling with depression.

For further information contact:

Glen Akselrod Investor Relations Greenbrook TMS Inc.

Email: investorrelations@greenbrooktms.com Phone: 1-855-797-4867

Forward-Looking Statements:

Certain information in this press release, including with respect to the Offering and continued marketing efforts in respect thereof, constitutes forward-looking information within the meaning of applicable securities laws in Canada and the United States, including the United States Private Securities Litigation

– 2 –

Reform Act of 1995. In some cases, but not necessarily in all cases, forward-looking information can be identified by the use of forward-looking terminology such as “plans”, “targets”, “expects” or “does not expect”, “is expected”, “an opportunity exists”, “is positioned”, “estimates”, “intends”, “assumes”, “anticipates” or “does not anticipate” or “believes”, or variations of such words and phrases or state that certain actions, events or results “may”, “could”, “would”, “might”, “will” or “will be taken”, “occur” or “be achieved”. In addition, any statements that refer to expectations, projections or other characterizations of future events or circumstances contain forward-looking information. Statements containing forward- looking information are not historical facts but instead represent management’s expectations, estimates and projections regarding future events.

Forward-looking information is necessarily based on a number of opinions, assumptions and estimates that, while considered reasonable by the Company as of the date of this press release, are subject to known and unknown risks, uncertainties, assumptions and other factors that may cause the actual results, level of activity, performance or achievements to be materially different from those expressed or implied by such forward-looking information, including but not limited to the factors described in greater detail in the “Risk Factors” section of the Company’s current annual information form and in the Company’s other materials filed with the Canadian securities regulatory authorities and the SEC from time to time, available at www.sedar.com and www.sec.gov, respectively, including the Prospectus and the Registration Statement. These factors are not intended to represent a complete list of the factors that could affect the Company; however, these factors should be considered carefully. There can be no assurance that such estimates and assumptions will prove to be correct. The forward-looking statements contained in this press release are made as of the date of this press release, and the Company expressly disclaims any obligation to update or alter statements containing any forward-looking information, or the factors or assumptions underlying them, whether as a result of new information, future events or otherwise, except as required by law.

May 7, 2021 – Toronto, Ontario – Greenbrook TMS Inc. (TSX: GTMS, NASDAQ: GBNH) (“Greenbrook” or the “Company”) announces today that it will postpone the release of its first quarter 2021 operational and financial results, originally scheduled for Wednesday, May 12, 2021. Greenbrook will now release its first quarter 2021 operational and financial results after market hours on Friday, May 14, 2021.

FIRST QUARTER 2021 CONFERENCE CALL DETAILS

Bill Leonard, President and Chief Executive Officer, and Erns Loubser, Chief Financial Officer, will host a conference call at 10:00 a.m. (Eastern Time) on Monday, May 17, 2021 to discuss the financial results for the quarter.

Dial in Numbers:

Toll Free North America: (866) 521-4909

Toronto: (647) 427-2311

Webcast:

For more information or to listen to the call via webcast, please visit: https://www.greenbrooktms.com/investors/events

For those that plan on accessing the conference call or webcast, please allow ample time prior to the call time.

Conference Call Replay:

Toll Free (North America): (800) 585-8367

Toronto: (416) 621-4642

Conference ID: 6679987

The conference call replay will be available from 1:00 p.m. ET on May 17, 2021, until 11:59 p.m. ET on June 17, 2021.

About Greenbrook TMS Inc.

Operating through 128 Company-operated treatment centers, Greenbrook is a leading provider of Transcranial Magnetic Stimulation (“TMS”) therapy, an FDA-cleared, non-invasive therapy for the treatment of Major Depressive Disorder and other mental health disorders, in the United States. TMS therapy provides local electromagnetic stimulation to specific brain regions known to be directly associated with mood regulation. Greenbrook has provided more than 620,000 TMS treatments to over 17,000 patients struggling with depression.

– 2 –

For further information please contact:

Glen Akselrod Investor Relations Greenbrook TMS Inc.

Contact Information: investorrelations@greenbrooktms.com 1-855-797-4867

May 4, 2021 – Toronto, Canada – Greenbrook TMS Inc. (TSX: GTMS) (NASDAQ: GBNH) (“Greenbrook” or the “Company”) today announces that it is pursuing an underwritten public offering of common shares (the “Common Shares”) in the United States and Canada (the “Offering”). The Common Shares are being offered by Stifel, Canaccord Genuity and BTIG, as joint book-running managers, and by Bloom Burton, as co-manager (collectively, the “Underwriters”).

The actual number of Common Shares to be distributed, the price of each Common Share and the size of the Offering will be determined by negotiation between the Company and the Underwriters in the context of the market with final terms to be determined at the time of pricing. The Offering is subject to market conditions, and there can be no assurance as to whether or when the Offering may be completed, or as to the actual size or terms of the Offering.

The Company intends to use the net proceeds from the proposed Offering for the development of new mental health service centers that specialize in Transcranial Magnetic Stimulation (“TMS”) treatment, to fund potential acquisitions as well as working capital and general corporate purposes.

The Offering is subject to a number of customary conditions, including, without limitation, receipt of all regulatory and stock exchange approvals. The Company has applied to list the Common Shares to be issued in the Offering on the Toronto Stock Exchange (“TSX”), subject to customary listing conditions, and has notified the Nasdaq Stock Market LLC (“NASDAQ”) in accordance with the rules of that exchange.

In connection with the Offering, the Company has filed and been receipted for a preliminary short form base PREP prospectus (the “Preliminary Prospectus”) with the securities regulatory authorities in each of the provinces of Canada, other than Québec. The Preliminary Prospectus has also been filed with the U.S. Securities and Exchange Commission (the “SEC”) as part of the Company’s registration statement on Form F-10 (the “Registration Statement”) in accordance with the U.S./Canada multi-jurisdictional disclosure system, but the Registration Statement has not yet become effective. The Preliminary Prospectus and the Registration Statement contain important information about the Company and the Offering. Prospective investors should read the Preliminary Prospectus and the Registration Statement and the other documents the Company has filed before making an investment decision. The Preliminary Prospectus is available on SEDAR at www.sedar.com. The Registration Statement is available on the SEC’s website at www.sec.gov. Alternatively, the Preliminary Prospectus (and the final short form base PREP prospectus for the Offering, when available), and the Registration Statement may be obtained, upon request, from the offices of Stifel, Nicolaus & Company, Incorporated at Attention: Syndicate, One Montgomery Street, Suite 3700, San Francisco, CA 94104, by telephone at (415) 364-2720, or by email at syndprospectus@stifel.com, from the offices of Canaccord Genuity LLC, 99 High Street, 12th Floor, Boston, Massachusetts 02110, Attn: Syndicate Department or by email at prospectus@cgf.com, or from the offices of BTIG at 65 East 55^th Street, New York NY 10022, or by email at prospectusdelivery@btig.com.

This press release does not constitute an offer to sell or the solicitation of an offer to buy securities, nor will there be any sale of the securities in any province, state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such province, state or jurisdiction. The securities being offered have not been approved or disapproved by any regulatory authority, nor has any such authority passed upon by the accuracy or adequacy of the Preliminary Prospectus or the Registration Statement. The securities described herein may not be sold nor may offers to buy be accepted prior to the time at which the Registration Statement becomes effective and the Company files the (final) short form base PREP prospectus.

– 2 –

About Greenbrook

Operating through 128 Company-operated treatment centers, Greenbrook is a leading provider of TMS therapy, an FDA-cleared, non-invasive therapy for the treatment of Major Depressive Disorder and other mental health disorders, in the United States. TMS therapy provides local electromagnetic stimulation to specific brain regions known to be directly associated with mood regulation. Greenbrook has provided more than 620,000 TMS treatments to over 17,000 patients struggling with depression.

For further information contact:

Glen Akselrod Investor Relations Greenbrook TMS Inc.

Contact information:

investorrelations@greenbrooktms.com 1-855-797-4867

Forward-Looking Statements:

Certain information in this press release, including with respect to the anticipated Offering, the listing of the Common Shares to be issued in the Offering on the TSX and NASDAQ, and the anticipated use of the net proceeds of the Offering, constitutes forward-looking information within the meaning of applicable securities laws in Canada and the United States, including the United States Private Securities Litigation Reform Act of 1995. In some cases, but not necessarily in all cases, forward-looking information can be identified by the use of forward-looking terminology such as “plans”, “targets”, “expects” or “does not expect”, “is expected”, “an opportunity exists”, “is positioned”, “estimates”, “intends”, “assumes”, “anticipates” or “does not anticipate” or “believes”, or variations of such words and phrases or state that certain actions, events or results “may”, “could”, “would”, “might”, “will” or “will be taken”, “occur” or “be achieved”. In addition, any statements that refer to expectations, projections or other characterizations of future events or circumstances contain forward-looking information. Statements containing forward- looking information are not historical facts but instead represent management’s expectations, estimates and projections regarding future events.

Forward-looking information is necessarily based on a number of opinions, assumptions and estimates that, while considered reasonable by the Company as of the date of this press release, are subject to known and unknown risks, uncertainties, assumptions and other factors that may cause the actual results, level of activity, performance or achievements to be materially different from those expressed or implied by such forward-looking information, including but not limited to the factors described in greater detail in the “Risk Factors” section of the Company’s current annual information form and in the Company’s other materials filed with the Canadian securities regulatory authorities and the SEC from time to time, available at www.sedar.com and www.sec.gov, respectively. These factors are not intended to represent a complete list of the factors that could affect the Company; however, these factors should be considered carefully. There can be no assurance that such estimates and assumptions will prove to be correct. The forward-looking statements contained in this press release are made as of the date of this press release, and the Company expressly disclaims any obligation to update or alter statements containing any forward-looking information, or the factors or assumptions underlying them, whether as a result of new information, future events or otherwise, except as required by law.

May 4, 2021 – Toronto, Ontario – Greenbrook TMS Inc. (TSX: GTMS, NASDAQ: GBNH) (“Greenbrook” or the “Company”) today announced certain preliminary unaudited operational and financial results for the first quarter ended March 31, 2021 (“Q1 2021”). All values in this news release are in United States dollars, unless otherwise stated.

PRELIMINARY Q1 2021 OPERATIONAL AND FINANCIAL HIGHLIGHTS

• New patient starts increased by 11% to 1,583 as compared to the fourth quarter of 2020 (“Q4 2020”) and by 19% as compared to the first quarter of 2020 (“Q1 2020”).
• Quarterly revenue is expected to be in the range of $11.1 million to $11.4 million, a sequential increase of between 12% to 15% as compared to Q4 2020 and a decrease of between 3% and 0% as compared to Q1 2020. This is despite a series of significant weather events, which led to temporary closures of many of our TMS centers across our network, and also includes provisions against
• Treatment volumes decreased by 4% to 52,126 as compared to Q4 2020 due to typical seasonal factors, amplified by harsh winter weather in parts of the United States. Despite these factors we managed year-over-year growth of 9% as compared to Q1 2020.
• Consultations performed, an important performance indicator for the Company, increased by 52% as compared to Q1 2020, which points to encouraging prospects for the remainder of

Bill Leonard, President and Chief Executive Officer of Greenbrook, commented:

“Despite a challenging operating environment, highlighted by a significant winter surge in the COVID-19 pandemic, unusual weather events, and historically typical Q1 seasonality, we are encouraged by our preliminary results, managing a strong bounce back in revenue from Q4 2020. We are proud of our team’s efforts to continue to treat patients suffering from treatment resistant depression and obsessive-compulsive disorder during this difficult time. Depression rates have increased significantly since the onset of the COVID-19 pandemic and we believe that our services are needed now more than ever. We are particularly excited about our leading indicators, with record highs in consultations performed and new patient starts, and at the prospect of leveraging this momentum throughout 2021.”

About Greenbrook TMS Inc.

Operating through 128 Company-operated treatment centers, Greenbrook is a leading provider of Transcranial Magnetic Stimulation (“TMS”) therapy, an FDA-cleared, non-invasive therapy for the treatment of Major Depressive Disorder and other mental health disorders, in the United States. TMS therapy provides local electromagnetic stimulation to specific brain regions known to be directly associated with mood regulation. Greenbrook has provided more than 620,000 TMS treatments to over 17,000 patients struggling with depression.

For further information please contact:

Glen Akselrod Investor Relations Greenbrook TMS Inc.

– 2 –

Contact Information:

investorrelations@greenbrooktms.com 1-855-797-4867

Cautionary Note Regarding Forward-Looking Information

Certain information in this press release, including with respect to the Company’s future financial or operating performance, constitutes forward-looking information within the meaning of applicable securities laws in Canada and the United States, including the United States Private Securities Litigation Reform Act of 1995. In some cases, but not necessarily in all cases, forward-looking information can be identified by the use of forward-looking terminology such as “plans”, “targets”, “expects” or “does not expect”, “is expected”, “an opportunity exists”, “is positioned”, “estimates”, “intends”, “assumes”, “anticipates” or “does not anticipate” or “believes”, or variations of such words and phrases or state that certain actions, events or results “may”, “could”, “would”, “might”, “will” or “will be taken”, “occur” or “be achieved”. In addition, any statements that refer to expectations, projections or other characterizations of future events or circumstances contain forward-looking information. Statements containing forward-looking information are not historical facts but instead represent management’s expectations, estimates and projections regarding future events.

Forward-looking information is necessarily based on a number of opinions, assumptions and estimates that, while considered reasonable by the Company as of the date of this press release, are subject to known and unknown risks, uncertainties, assumptions and other factors that may cause the actual results, level of activity, performance or achievements to be materially different from those expressed or implied by such forward-looking information, including but not limited to the factors described in greater detail in the “Risk Factors” section of the Company’s current annual information form and in the Company’s other materials filed with the Canadian securities regulatory authorities and the United States Securities and Exchange Commission from time to time, available at www.sedar.com and www.sec.gov, respectively. These factors are not intended to represent a complete list of the factors that could affect the Company; however, these factors should be considered carefully. There can be no assurance that such estimates and assumptions will prove to be correct. The forward-looking statements contained in this press release are made as of the date of this press release, and the Company expressly disclaims any obligation to update or alter statements containing any forward-looking information, or the factors or assumptions underlying them, whether as a result of new information, future events or otherwise, except as required by law.

April 20, 2021 – Toronto, Ontario – Greenbrook TMS Inc. (TSX: GTMS, NASDAQ: GBNH) (“Greenbrook” or the “Company”), will release its first quarter 2021 operational and financial results after market hours on May 12, 2021.

FIRST QUARTER 2021 CONFERENCE CALL DETAILS

Bill Leonard, President and Chief Executive Officer, and Erns Loubser, Chief Financial Officer, will host a conference call at 10:00 a.m. (Eastern Time) on May 13, 2021 to discuss the financial results for the quarter.

Dial in Numbers:

Toll Free North America: (866) 521-4909

Toronto: (647) 427-2311

Webcast:

For more information or to listen to the call via webcast, please visit: https://www.greenbrooktms.com/investors/events

For those that plan on accessing the conference call or webcast, please allow ample time prior to the call time.

Conference Call Replay:

Toll Free (North America): (800) 585-8367

Toronto: (416) 621-4642

Conference ID: 6679987

The conference call replay will be available from 1:00 p.m. ET on May 13, 2021, until 11:59 p.m. ET on June 12, 2021.

CORPORATE UPDATE

Greenbrook also announced today that Erns Loubser will be returning to the role of Chief Financial Officer and Treasurer following his previously announced medical leave of absence. In connection with Mr. Loubser’s return, Ed Cordell will be stepping down from his role as Interim Chief Financial Officer but will remain with the Company until his responsibilities have been fully transitioned to Mr. Loubser.

– 2 –

About Greenbrook TMS Inc.

Operating through 128 Company-operated treatment centers, Greenbrook is a leading provider of Transcranial Magnetic Stimulation (“TMS”) therapy, an FDA-cleared, non-invasive therapy for the treatment of Major Depressive Disorder and other mental health disorders, in the United States. TMS therapy provides local electromagnetic stimulation to specific brain regions known to be directly associated with mood regulation. Greenbrook has provided more than 560,000 TMS treatments to over 15,000 patients struggling with depression.

For further information please contact:

Glen Akselrod Investor Relations Greenbrook TMS Inc.

Contact Information: investorrelations@greenbrooktms.com 1-855-797-4867

March 15, 2021 – Toronto, Ontario – Greenbrook TMS Inc. (TSX: GTMS) (“Greenbrook” or the “Company”) is pleased to announce that its common shares have been approved for listing and trading in

U.S. dollar currency on the NASDAQ Stock Market LLC (“NASDAQ”). Trading on the NASDAQ will commence at the start of trading on March 16, 2021 under the symbol “GBNH”. Greenbrook’s common shares will continue trading on the Toronto Stock Exchange in Canadian dollar currency under the symbol “GTMS”.

“The listing of our common shares on the NASDAQ marks a significant milestone in the history of our Company”, commented Bill Leonard, President and Chief Executive Officer of Greenbrook. “We believe that the NASDAQ listing will provide significant benefits, including increased visibility of the Company amongst investors, increased access to capital and potential for greater liquidity”.

About Greenbrook TMS Inc.

Operating through 126 Company-operated treatment centers, Greenbrook is a leading provider of Transcranial Magnetic Stimulation (“TMS”) therapy, an FDA-cleared, non-invasive therapy for the treatment of Major Depressive Disorder and other mental health disorders, in the United States. TMS therapy provides local electromagnetic stimulation to specific brain regions known to be directly associated with mood regulation. Greenbrook has provided more than 510,000 TMS treatments to over 14,000 patients struggling with depression.

For further information please contact:

Glen Akselrod Investor Relations Greenbrook TMS Inc.

Contact Information:

investorrelations@greenbrooktms.com 1-855-797-4867

Cautionary Note Regarding Forward-Looking Information

Certain information in this press release, including with respect to the trading of Greenbrook’s common shares on the NASDAQ, constitute forward-looking information. In some cases, but not necessarily in all cases, forward-looking information can be identified by the use of forward-looking terminology such as “plans”, “targets”, “expects” or “does not expect”, “is expected”, “an opportunity exists”, “is positioned”, “estimates”, “intends”, “assumes”, “anticipates” or “does not anticipate” or “believes”, or variations of such words and phrases or state that certain actions, events or results “may”, “could”, “would”, “might”, “will” or “will be taken”, “occur” or “be achieved”. In addition, any statements that refer to expectations, projections or other characterizations of future events or circumstances contain forward-looking information. Statements containing forward-looking information are not historical facts but instead represent management’s expectations, estimates and projections regarding future events.

Forward-looking information is necessarily based on a number of opinions, assumptions and estimates that, while considered reasonable by the Company as of the date of this press release, are subject to known and unknown risks, uncertainties, assumptions and other factors that may cause the actual results, level of activity, performance or achievements to be materially different from those expressed or implied by such forward-looking information, including but not limited to the factors described in greater detail in the “Risk

– 2 –

Factors” section of the Company’s current annual information form available at www.sedar.com and www.sec.gov. These factors are not intended to represent a complete list of the factors that could affect the Company; however, these factors should be considered carefully. There can be no assurance that such estimates and assumptions will prove to be correct. The forward-looking statements contained in this press release are made as of the date of this press release, and the Company expressly disclaims any obligation to update or alter statements containing any forward-looking information, or the factors or assumptions underlying them, whether as a result of new information, future events or otherwise, except as required by law.