The three-volume set LNCS 13747, LNCS 13748 and LNCS 13749 constitutes the refereed proceedings of the 20th International Conference on Theory of Cryptography, TCC 2022, held in Chicago, IL, USA, in November 2022. The total of 60 full papers presented in this three-volume set was carefully reviewed and selected from 139 submissions. They cover topics on post-quantum cryptography; interactive proofs; quantum cryptography; secret-sharing and applications; succinct proofs; identity-based encryption and functional encryption; attribute-based encryption and functional encryption; encryption; multi-party computation; prools: key agreement and commitments; theory: sampling and friends; lattices; anonymity, verfiability and robustness; ORAM, OT and PIR; and theory.