Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ Annual Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the fiscal year ended September 30, 2023 ☐ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Commission File Number: 1-14222 SUBURBAN PROPANE PARTNERS, L.P. (Exact name of registrant as specified in its charter) Delaware 22-3410353 (State or other jurisdiction of (I.R.S. Employer i ...