UNITED STATES
 SECURITIES AND EXCHANGE COMMISSION
 WASHINGTON, D.C. 20549
 FORM 10-K/A
 (Amendment No. 1)
 (Mark One)

 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

 For the fiscal year ended December 31, 2023
 OR

 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

 For the transition period from ___________ to ___________.
 Commission File Number: 001-34811
 Ameresco, Inc.
 (Exact name of registrant as specified in its charter)

 Delaware

 04-3512838

 (State or Other Jurisdiction of
Incorporation or Organization)

 (I.R.S. Employer
Identification No.)

 111 Speen Street, Suite 410
 Framingham, Massachusetts

 01701

 (Address of Principal Executive Offices)

 (Zip Code)

 ( 508) 661-2200
 (Registrant's Telephone Number, Including Area Code)
 Securities registered pursuant to Section 12(b) of the Act:

 Title of each class
 Trading Symbol
 Name of each exchange on which registered

 Class A Common Stock, par value $0.0001 per share
 AMRC
 New York Stock Exchange

 Securities registered pursuant to Section 12(g) of the Act: None
 Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes No
 Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes No
 Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports) and (2) has been subject to such filing requirements for the past 90 days. Yes No
 Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes No
 Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

 Large Accelerated Filer

 Accelerated Filer

 Non-accelerated filer

 Smaller reporting company

 Emerging growth company

 If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

 Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.
 If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.
 Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant's executive officers during the relevant recovery period pursuant to § 240.10D-1(b).

 Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes No
 The aggregate market value of the voting and non-voting common equity held by non-affiliates computed by reference to the price at which the common equity was last sold on the New York Stock Exchange on June 30, 2023, the last business day of the registrant's most recently completed second fiscal quarter, was $ 1,550,437,708.
 Indicate the number of shares outstanding of each of the registrant's classes of common stock as of the latest practicable date.

 Class
 Shares outstanding as of February 23, 2024

 Class A Common Stock, $0.0001 par value per share
 34,282,945

 Class B Common Stock, $0.0001 par value per share
 18,000,000

 Auditor Name:
 RSM US LLP

 Auditor Location:
 Boston, Massachusetts

 PCAOB ID:

 DOCUMENTS INCORPORATED BY REFERENCE
 Portions of the definitive proxy statement for our 2024 annual meeting of stockholders are incorporated by reference into Part III.

 EXPLANATORY NOTE
 This Amendment No. 1 ("Amendment No. 1" or "Form 10-K/A") amends the Annual Report on Form 10-K for the period ended December 31, 2023, originally filed on February 29, 2024 (the "Original Form 10-K") of Ameresco, Inc. (the "Company", "we" or "our") solely to include Exhibit 97.1 to the Form 10-K/A, our Dodd-Frank Compensation Recovery Policy, which was inadvertently omitted. There are no other changes to the Original Form 10-K.
 This Form 10-K/A speaks as of the original filing date of the Original Form 10-K, does not reflect events that may have occurred subsequent to the original filing date, and does not modify or update in any way disclosures made in the Original Form 10-K. Accordingly, this Form 10-K/A should be read in conjunction with the Original Form 10-K.

 Item 15. Exhibits and Financial Statement Schedules

 (a)(1)
 Financial Statements: See "Index to Consolidated Financial Statements"

 (a)(2)
 Financial Statement Schedules: None

 Schedules are omitted because they are not applicable, or are not required, or because the information is included in the consolidated financial statements and notes thereto.

 (a)(3)
 Exhibits:

 Exhibit Number
 Exhibit Description

 3.1
 Restated Certificate of Incorporation of Ameresco, Inc. Filed as Exhibit 3.1 to our Current Report on Form 8-K dated July 27, 2010 and filed with the Commission on July 30, 2010 and incorporated herein by reference.

 3.2
 Second Amended and Restated By-Laws of Ameresco, Inc. Filed as Exhibit 3.1 to our Current Report on Form 8-K filed with the Commission on April 24, 2023 and incorporated herein by reference.

 4.1
 Specimen Certificate evidencing shares of Class A common stock. Filed as Exhibit 4.1 to our Registration Statement on Form S-1 (pre-effective amendment no. 4; reg. no. 333-165821) and incorporated herein by reference.

 4.16

 Description of Ameresco, Inc. Securities Registered under Section 12 of the Exchange Act. Filed as Exhibit 4.16 to our Annual Report on Form 10-K for the year ended December 31, 2019 and filed with the Commission on March 4, 2020 and incorporated herein by reference.

 10.1.1
 Fifth Amended and Restated Credit Agreement dated as of March 4, 2022 among Ameresco, Inc., certain of its subsidiaries, the lenders (as defined therein), BOFA Securities, Inc. as sole lead arranger and sole bookrunner and Bank of America, N.A. as Administrative Agent. Filed as Exhibit 10.1 to our Current Report on Form 8-K filed with the Commission on March 4, 2022 and incorporated herein by reference.

 10.1.2
 Amendment No. 1 to Fifth Amended and Restated Credit Agreement dated as of June 9, 2022 among Ameresco, Inc., certain of its subsidiaries, the lenders (as defined therein), BOFA Securities, Inc. as sole lead arranger and sole bookrunner and Bank of America, N.A. as administrative agent. Filed as Exhibit 10.1 to our Form 10-Q for the quarter ended June 30, 2022 and filed with the Commission on August 2, 2023

 10.1.3
 Amendment No. 2 to Fifth Amended and Restated Credit Agreement dated March 17, 2023 among Ameresco, Inc., certain guarantors party thereto, certain lenders party thereto from time to time and Bank of America, N.A. as Administrative Agent. Filed as Exhibit 10.3 to our Form 10-Q for the quarter ended March 31, 2023 and filed with the Commission on May 2, 2023.

 10.1.4
 Amendment No. 3 to Fifth Amended and Restated Credit Agreement dated as of August 24, 2023 among Ameresco, Inc., certain of its subsidiaries, the lenders (as defined therein), BOFA Securities, Inc. as sole lead arranger and sole bookrunner and Bank of America, N.A. as administrative agent. Filed as Exhibit 10.1 to our Current Report on Form 8-K filed with the Commission on August 24, 2023 and incorporated herein by reference.

 10.1.5
 Amendment No. 4 to Fifth Amended and Restated Credit Agreement dated as of December 11, 2023 among Ameresco, Inc., certain of its subsidiaries, the lenders (as defined therein), and Bank of America, N.A. as Administrative Agent. Filed as Exhibit 10.1 to our Current Report on Form 8-K filed with the Commission on December 11, 2023 and incorporated herein by reference.

 10.3.1+

 Ameresco, Inc. 2010 Stock Incentive Plan. Filed as Exhibit 10.10 to our Registration Statement on Form S-1 (pre-effective amendment no. 4; reg. no. 333-165821) and incorporated herein by reference.

 10.3.2+

 Form of Incentive Stock Option Agreement granted under Ameresco, Inc. 2010 Stock Incentive Plan. Filed as Exhibit 10.11 to our Registration Statement on Form S-1 (pre-effective amendment no. 4; reg. no. 333-165821) and incorporated herein by reference.

 Exhibit
Number
 Description

 10.3.3+

 Form of Director Stock Option Agreement granted under Ameresco, Inc. 2010 Stock Incentive Plan. Filed as Exhibit 10.12 to our Registration Statement on Form S-1 (pre-effective amendment no. 4; reg. no. 333-165821) and incorporated herein by reference.

 10.4.1+
 Ameresco, Inc. 2020 Stock Incentive Plan. Filed as Exhibit 99.2 Ameresco, Inc. 2020 Stock Incentive Plan. Filed as Exhibit 99.2 to our Registration Statement on Form S-8 (reg. no. 333-238792) and incorporated herein by reference.

 10.4.2+
 Form of Incentive Stock Option Agreement granted under Ameresco, Inc. 2020 Stock Incentive Plan. Filed as Exhibit 10.2 to our Quarterly Report on Form 10-Q for the fiscal quarter ended June 30, 2020.

 10.4.3+
 Form of Director Stock Option Agreement granted under Ameresco, Inc. 2020 Stock Incentive Plan. Filed as Exhibit 10.3 to our Quarterly Report on Form 10-Q for the fiscal quarter ended June 30, 2020.

 10.5.1+

 Form of Indemnification Agreement entered into between Ameresco, Inc. and each non-employee director. Filed as Exhibit 10.6.1 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2010 and filed with the Commission on March 31, 2011 and incorporated herein by reference.

 10.5.2+

 Form of Indemnification Agreement entered into between Ameresco, Inc. and each employee director. Filed as Exhibit 10.6.2 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2010 and filed with the Commission on March 31, 2011 and incorporated herein by reference.

 10.6+

 Ameresco, Inc. 2017 Employee Stock Purchase Plan, as amended. Filed as Exhibit 10.8 to our Quarterly Report on Form 10-Q for the fiscal quarter ended June 30, 2020 and filed with the Commission on August 4, 2020 and incorporated herein by reference.

 10.7+

 Ameresco, Inc. Executive Management Team Additional Annual Incentive Performance Program. Filed as Exhibit 10.1 to our Quarterly Report on Form 10-Q for the fiscal quarter ended June 30, 2019 and filed with the Commission on August 8, 2019 and incorporated herein by reference.

 10.8+

 Offer Letter between the Company and Doran Hole dated June 26, 2019. Filed as Exhibit 10.1 to our Current Report on Form 8-k filed with the Commission on July 1, 2019 and incorporated herein by reference.

 10.9#
 Turnkey Engineering, Procurement, Construction and Maintenance Agreement dated as of October 21, 2021, by and between Ameresco, Inc. and Southern California Edison Company. Filed as Exhibit 10.10 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2022 filed with the Commission on February 28, 2023 and incorporated herein by reference.

 10.10+
 Form of Non-Employee Director Restricted Stock Unit Agreement. Filed as Exhibit 10.11 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2022 filed with the Commission on February 28, 2023 and incorporated herein by reference.

 10.11+
 Ameresco, Inc. Form of 2023 Executive/Employee RSU Award Agreement. Filed as Exhibit 10.11 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 filed with the Commission on February 29, 2024 and incorporated herein by reference.

 10.12+
 Non-Employee Director Compensation Policy. Filed as Exhibit 10.12 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2022 filed with the Commission on February 28, 2023 and incorporated herein by reference.

 21.1

 Subsidiaries of Ameresco, Inc. Filed as Exhibit 21.1 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 filed with the Commission on February 29, 2024 and incorporated herein by reference..

 23.1
 Consent of RSM US LLP. Filed as Exhibit 23.1 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 filed with the Commission on February 29, 2024 and incorporated herein by reference.

 31.1*

 Principal Executive Officer Certification required by Rule 13a-14(a) or Rule 15d-14(a) of the Securities Exchange Act of 1934, as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

 31.2*

 Principal Financial Officer Certification required by Rule 13a-14(a) or Rule 15d-14(a) of the Securities Exchange Act of 1934, as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

 32.1**

 Certifications pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

 97.1*
 Ameresco, Inc. Dodd-Frank Compensation Recovery Policy

 104*

 Exhibit
Number
 Description

 *
 Filed herewith.

 **
 Furnished herewith.

 +
 Identifies a management contract or compensatory plan or arrangement in which an executive officer or director of Ameresco participates.

 #
 Certain portions of this exhibit are considered confidential and have been omitted as permitted under SEC rules and regulations. Schedules and exhibits have been omitted pursuant to Item 601(b)(2) of Regulation S-K.

 SIGNATURE
 Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

 AMERESCO, INC.

 Date: March 11, 2024

 By:
 /s/ George P. Sakellaris

 George P. Sakellaris

 President and Chief Executive Officer