This volume constitutes the proceedings of the 13th International Conference on post-quantum cryptography, PQCrypto 2022, held in as a Virtual Event in September 2022. The 23 full papers presented in this volume were carefully reviewed and selected from 66 submissions. They cover a broad spectrum of research within the conference's scope, including code-, hash-, isogeny-, and lattice-based cryptography, multivariate cryptography, and quantum cryptanalysis. The papers are categorized in the following topical sub-headings: Code-Based Cryptography; Multivariate Cryptography and the MinRank Problem; Quantum Algorithims, Attacks and Models; Implementation and Side Channel Attacks; Isogeny; Lattice-based Cryptography; Cryptanalysis.