UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

Amendment No. 3 to
Form 10-K

Commission File Number: 333-178082

XENETIC BIOSCIENCES, INC.

(Exact name of registrant as specified in its charter)

Indicate by check mark if the registrant is a well known seasoned issuer, as defined in Rule 405 of the Securities Act:    Yes  ¨    No  x

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  x    No  o

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  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted 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 and post such files):    Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K:    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Exchange Act Rule 12b-2):    Yes  ¨    No  x

The approximate aggregate market value of voting common stock held by non-affiliates of the registrant, based upon the last sale price of the registrant’s common stock on the last business day of the registrant’s most recently completed second fiscal quarter June 30, 2013 (based upon the shares of common stock at the closing sale price of the registrant’s common stock listed as reported on the OTC Bulletin Board), was approximately $700,000. Note, however, that this was prior to the Acquisition described herein.

As of April 15, 2014 the number of outstanding shares of the registrant’s common stock was 146,740,692.

DOCUMENTS INCORPORATED BY REFERENCE

The registrant intends to file a proxy statement pursuant to Regulation 14A or a Form 10-K/A, not later than 120 days after the close of the fiscal year ended December 31, 2013. Portions of such proxy statement or Form 10-K/A are incorporated by reference into Part III of this Annual Report on Form 10-K.

EXPLANATORY NOTE

The Registrant is filing this Amendment No. 3 on Form 10-K/A (“Form 10-K/A”) to its Annual Report on Form 10-K for the fiscal year ended December 31, 2013 (“Form 10-K”) to indicate that we are not required to file reports pursuant to Section 13 or Section 15(d) of the Act.

Except as described above, there have been no other changes to the Annual Report filed on Form 10-K filed with the SEC on April 15, 2014. This Form 10-K/A does not purport to reflect any information or events subsequent to the filing thereof. As such, this Form 10-K/A speaks only as of the date the Form 10-K was filed, and the Registrant has not undertaken herein to amend, supplement or update any information contained in the Form 10-K to give effect to any subsequent events. Accordingly, this Form 10-K/A should be read in conjunction with the Form 10-K.

SIGNATURES

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.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities indicated below on the 20th day of July, 2015.

EXHIBIT INDEX