This book constitutes the refereed proceedings of the 17th International Conference on Cryptology in Africa, AFRICACRYPT 2026, which took place in Hammamet, Tunisia in July 8–10, 2026.The 19 full papers included in this volume were carefully reviewed and selected from 57 submissions. They are grouped into the following topics: Lattice-Based and Post-Quantum Cryptography; Quantum and Post-Quantum Attacks/Protocols; Fully Homomorphic Encryption; Symmetric Cryptography and Implementation Security; ECC, Pairings, and RSA; Advanced Signatures; and Cryptographic Models and Applications.