Document

We are acting as special counsel to Compass, Inc., a Delaware corporation (the “Company”), in connection with the filing by the Company of a Registration Statement on Form S-8 (the “Registration Statement”) under the Securities Act of 1933, as amended (the “Act”), with the Securities and Exchange Commission (the “Commission”) covering the offering of up to (i) 28,175,633 additional shares of its Class A common stock, $0.00001 par value per share (the “EIP Shares”) available for issuance under the Registrant’s 2021 Equity Incentive Plan (“2021 EIP”), pursuant to the provision of the 2021 EIP providing for an automatic annual increase in the number of shares reserved for issuance and (ii) 5,533,902 additional shares of its Class A common stock (the “ESPP Shares,” collectively with the EIP Shares, the “Plan Shares”) available for issuance under the Registrant’s 2021 Employee Stock Purchase Plan (“2021 ESPP” and, collectively with the 2021 EIP, the “Plans”), pursuant to the provision of the 2021 ESPP providing for an automatic annual increase in the number of shares reserved for issuance.

For purposes of this letter, we have examined such documents, records, certificates, resolutions and other instruments deemed necessary as a basis for this opinion, and we have assumed the authenticity of all documents submitted to us as originals, the conformity to the originals of all documents submitted to us as copies and the authenticity of the originals of all documents submitted to us as copies.

Based upon and subject to the foregoing qualifications, assumptions and limitations and the further limitations set forth herein, we advise you that the Plan Shares are duly authorized and when the Plan Shares have been duly issued pursuant to and in accordance with the terms and conditions of the applicable Plans and the Company’s Restated Certificate of Incorporation and Amended and Restated Bylaws, the Plan Shares will be validly issued, fully paid and non-assessable.

We have relied without independent investigation upon, among other things, an assurance from the Company that the number of shares which the Company is authorized to issue in its Restated Certificate of Incorporation exceeds the number of shares outstanding and the number of shares which the Company is obligated to issue (or had otherwise reserved for issuance) for any purposes other than issuances of the Plan Shares by at least the number of Plan Shares and we have assumed that such condition will remain true at all future times relevant to this opinion.

We hereby consent to the filing of this opinion with the Commission as Exhibit 5.1 to the Registration Statement. In giving this consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission.

We do not find it necessary for the purposes of this opinion, and accordingly we do not purport to cover herein, the application of the securities or “Blue Sky” laws of the various states to the issuance and sale of the Plan Shares.

This opinion is limited to the specific issues addressed herein, and no opinion may be inferred or implied beyond that expressly stated herein. We assume no obligation to revise or supplement this opinion should the General Corporation Law of the State of Delaware be changed by legislative action, judicial decision or otherwise.


Exhibit 5.1
	601 Lexington Avenue New York, NY 10022 United States +1 212 446 4800 www.kirkland.com	Facsimile: +1 212 446 4900


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Compass, Inc. February 27, 2026 Page 2