As filed with the Securities and Exchange Commission on June 19, 2020 RegistrationNo. 333-112221 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Post-Effective Amendment No. 1 to FormS-3 Registration StatementNo. 333-112221 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 John B. Sanfilippo & Son, Inc. (Exact name of registrant as specified in its charter) Delaware 36-2419677 (State or other jurisdiction of incorporation or organization) (I.R.S. Employer Identification Number) 1703 Randall Road, Elgin, Illinois 60123 (Address of Principal Executive Offices, including Zip Code) Michael J. Valentine Chief Financial Officer, Group President and Secretary John B. Sanfilippo & Son, Inc. 1703 Randall Road Elgin, Illinois 60123 (847) 289-1800 (Name, address and telephone number, including area code, of agent for service) Copies of all communications, including copies of all communications sent to agent for service, should be sent to: Alexander J. May and Donald Batterson Jenner & Block LLP 353 N. Clark Street Chicago, Illinois 60654-3456 (312)222-9350 APPROXIMATE DATE OF PROPOSED SALE TO THE PUBLIC: Not applicable. If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans check the following box. ☐ If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐ If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration number of the earlier effective registration statement for the same offering. ☐ If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, anon-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 Rule12b-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 comply with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act ☐ EXPLANATORY NOTE / DEREGISTRATION OF UNSOLD SECURITIES John B. Sanfilippo & Son, Inc. (the “Company”) registered the public offer and sale from time to time pursuant to the Securities Act of 1933, as amended, shares of the common stock, par value $0.01 per share of the Company (the “Registered Securities”), pursuant to the following registration statement (as amended, the “Registration Statement”): FormS-3 Registration StatementNo. 333-112221, originally filed with the Securities and Exchange Commission on January 27, 2004. The Company is filing this post-effective amendment to the Registration Statement (“Post-Effective Amendment”) in order to remove from registration any Registered Securities registered and unsold under the Registration Statement and to terminate the Registration Statement.