Exhibit 5.1


	10250 Constellation Blvd., Suite 1100
	Los Angeles, California 90067
	Tel: +1.424.653.5500 Fax: +1.424.653.5501
	www.lw.com

	FIRM / AFFILIATE OFFICES
	Beijing	Moscow
	Boston	Munich
	Brussels	New York
	Century City	Orange County
	Chicago	Paris
	Dubai	Riyadh
	Düsseldorf	San Diego
	Frankfurt	San Francisco
May 19, 2022 The Oncology Institute, Inc. 18000 Studebaker Rd. Cerritos, California 90703	Hamburg	Seoul
		Hong Kong	Shanghai
		Houston	Silicon Valley
		London	Singapore
		Los Angeles	Tokyo
		Madrid	Washington, D.C.
		Milan

Re: The Oncology Institute, Inc. – Registration Statement on Form S-1

To the addressees set forth above:

We have acted as special counsel to The Oncology Institute, Inc., a Delaware corporation (the “Company”), in connection with its filing on the date hereof with the Securities and Exchange Commission (the “Commission”) of a registration statement on Form S-1 (as amended, the “Registration Statement”) under the Securities Act of 1933, as amended (the “Act”), relating to the registration of the offer and sale from time to time of (i) 1,291,492 shares (the “RSU Shares”) of common stock, par value $0.0001 per share of the Company (the “Common Stock”) issuable upon the vesting of restricted stock units of the Company pursuant to the applicable restricted stock agreements (each, an “RSU Agreement”) and (ii) 50,584 shares of Common Stock (the “Earnout Resale Shares” and, together with the RSU Shares, the “Shares”) issued in connection with the business combination pursuant to the Agreement and Plan of Merger, dated as of June 28, 2021, by and among the Company, Orion Merger Sub I, Inc., Orion Merger Sub II, LLC and TOI Parent Inc. (the “Merger Agreement”) and subject to vesting pursuant to the earnout provisions therein, in each case by the selling securityholders named in the Registration Statement (the “Selling Securityholders”). This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement or related prospectus or prospectus supplement (collectively, the “Prospectus”) other than as expressly stated herein with respect to the Shares.

As such counsel, we have examined such matters of fact and questions of law as we have considered appropriate for purposes of this letter. With your consent, we have relied upon certificates and other assurances of officers of the Company and others as to factual matters without having independently verified such factual matters. We are opining herein as to the General Corporation Law of the State of Delaware (the “DGCL”) and we express no opinion with respect to the applicability thereto, or the effect thereon, of the laws of any other jurisdiction or, in

May 19, 2022

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the case of Delaware, any other laws, or as to any matters of municipal law or the laws of any local agencies within any state.

Subject to the foregoing and the other matters set forth herein, it is our opinion that, as of the date hereof:

When the RSU Shares have been duly registered on the books of the transfer agent and registrar therefor in the name or on behalf of the recipients thereof, and have been issued by the Company in the circumstances contemplated by and pursuant to the applicable RSU Agreement and assuming in each case that the individual issuances, grants or awards under the applicable RSU Agreement are duly authorized by all necessary corporate action and duly issued, granted or awarded and exercised in accordance with the requirements of law and the applicable RSU Agreement, the RSU Shares will have been duly authorized by all necessary corporate action of the Company and will be validly issued, fully paid and nonassessable.

The Earnout Resale Shares have been duly authorized by all necessary corporate action of the Company and are validly issued and, upon the vesting of the Earnout Resale Shares in accordance with the earnout provisions of the Merger Agreement, the Earnout Resale Shares will be, fully paid and nonassessable.

We express no opinion as to (a) any provision for liquidated damages, default interest, late charges, monetary penalties, make-whole premiums or other economic remedies to the extent such provisions are deemed to constitute a penalty, (b) consents to, or restrictions upon, governing law, jurisdiction, venue, arbitration, remedies or judicial relief, (c) waivers of rights or defenses, (d) any provision requiring the payment of attorneys’ fees, where such payment is contrary to law or public policy, (e) the creation, validity, attachment, perfection or priority of any lien or security interest, (f) advance waivers of claims, defenses, rights granted by law or notice, opportunity for hearing, evidentiary requirements, statutes of limitation, trial by jury or at law or other procedural rights, (g) waivers of broadly or vaguely stated rights, (h) provisions for exclusivity, election or cumulation of rights or remedies, (i) provisions authorizing or validating conclusive or discretionary determinations, (j) grants of setoff rights, (k) proxies, powers and trusts, (l) provisions prohibiting, restricting or requiring consent to assignment or transfer of any right or property, (m) any provision to the extent it requires that a claim with respect to a security denominated in other than U.S. dollars (or a judgment in respect of such a claim) be converted into U.S. dollars at a rate of exchange at a particular date, to the extent applicable law otherwise provides, and (n) the severability, if invalid, of provisions to the foregoing effect.

With your consent, we have assumed that (a) each RSU Agreement has been duly authorized, executed and delivered by the parties thereto other than the Company, (b) each RSU Agreement constitutes or will constitute legally valid and binding obligations of the parties thereto other than the Company, enforceable against each of them in accordance with their respective terms and (c) the status of each RSU Agreement as legally valid and binding obligations of the parties will not be affected by any (i) breaches of, or defaults under, agreements or instruments, (ii) violations of statutes, rules, regulations or court or governmental orders or (iii) failures to obtain required consents, approvals or authorizations from, or to make required registrations, declarations or filings with, governmental authorities.

May 19, 2022

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This opinion is for your benefit in connection with the Registration Statement and may be relied upon by you and by persons entitled to rely upon it pursuant to the applicable provisions of the Act. We consent to your filing this opinion as an exhibit to the Registration Statement and to the reference to our firm contained in the Prospectus under the heading “Legal Matters.” In giving such 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 thereunder.

	Sincerely,

	/s/ Latham & Watkins LLP