Exhibit 5.1

Akerman LLP Las Olas Centre II, Suite 1600 350 East Las Olas Boulevard Fort Lauderdale, FL  33301-2999 T: 954 463 2700 F: 954 463 2224

March 7, 2019

Xenetic Biosciences, Inc.

40 Speen Street, Suite 102

Framingham, Massachusetts 01701

RE: Xenetic Biosciences, Inc.

Ladies and Gentlemen:

You have requested our opinion, as counsel to Xenetic Biosciences, Inc., a Nevada corporation (the “Company”), with respect to certain matters in connection with the offering by the Company of 1,040,000 shares (the “Shares”) of Company common stock (the “Common Stock”) and pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to 509,000 shares of Common Stock (the “Pre-Funded Warrant Shares”, and, collectively with the Shares, the “Securities”) pursuant to a Registration Statement on Form S-3 (Registration Statement No. 333-227572) (the “Registration Statement”), filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Act”), the prospectus dated October 12, 2018 (the “Base Prospectus”), and the prospectus supplement dated March 5, 2019, filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations of the Act (together with the Base Prospectus, the “Prospectus”). The Shares, the Pre-Funded Warrants, and the Pre-Funded Warrant Shares are to be sold by the Company as described in the Registration Statement and the Prospectus.

In connection with this opinion, we have examined and relied upon the Registration Statement and Prospectus, the form of Pre-Funded Warrant, the Company’s Articles of Incorporation, as amended, its Amended and Restated Bylaws and the originals or copies certified to our satisfaction of such records, documents, certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness and authenticity of all documents submitted to us as originals, and the conformity to originals of all documents submitted to us as copies thereof and the due execution and delivery of all documents by all persons other than the Company where due execution and delivery are a prerequisite to the effectiveness thereof.

With regard to our opinion regarding the Pre-Funded Warrants and the Pre-Funded Warrant Shares, we express no opinion to the extent that, notwithstanding its current reservation of shares of Common Stock, future issuances of securities, including the Pre-Funded Warrant Shares, of the Company and/or antidilution adjustments to outstanding securities, including the Pre-Funded Warrants, of the Company cause the Pre-Funded Warrants to be exercisable for more shares of Common Stock than the number that then remain authorized but unissued.

Xenetic Biosciences, Inc.

March 7, 2019

Page 2

With regard to our opinion concerning the Pre-Funded Warrants constituting valid and binding obligations of the Company:

For purposes of this opinion, we assume the corporate laws of Nevada are substantially similar to the corporate laws of Florida and we express no opinion as to matters governed by laws of any jurisdiction other than Florida and New York. We neither express nor imply any obligation with respect to any other laws or the laws of any other jurisdiction or of the United States. For purposes of this opinion, we assume the Securities will be issued in compliance with all applicable state securities or blue sky laws. Further, we have assumed the Exercise Price (as defined in the Pre-Funded Warrants) will not be adjusted to an amount below the par value per share of the Common Stock.

In addition, our opinion herein is subject to, and may be limited by, (a) applicable bankruptcy, reorganization, insolvency, moratorium, fraudulent conveyance, debtor and creditor, and similar laws which relate to or affect creditors’ rights generally, and (b) general principles of equity (including, without limitation, concepts of materiality, reasonableness, good faith and fair dealing) regardless of whether considered in a proceeding in equity or at law.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that (i) the Shares, when sold in accordance with the Registration Statement and the Prospectus, will be validly issued, fully paid and nonassessable, (ii) provided that the Pre-Funded Warrants have been duly executed and delivered by the Company and duly delivered to the purchasers thereof against payment therefor, the Pre-Funded Warrants, when issued and sold as contemplated in the Registration Statement and the Prospectus will be valid and legally binding obligations of the Company, enforceable against the Company in accordance with their terms, and (iii) the Pre-Funded Warrant Shares, when issued and paid for in accordance with the terms of the Pre-Funded Warrants, will be validly issued, fully paid and nonassessable.

We consent to the reference to our firm under the caption “Legal Matters” in the Prospectus, the filing of this opinion as an exhibit to a current report on Form 8-K of the Company and the incorporation by reference of this opinion in the Registration Statement.