This book constitutes the refereed proceedings of the 11th International Conference on Tests and Proofs, TAP 2017, held as part of STAF 2017, in Marburg, Germany, in July 2017. The 9 full papers and 1 invited paper presented in this volume were carefully reviewed and selected from 16 submissions. The TAP conference promotes research in verification and formal methods that targets the interplay of proofs and testing: the advancement of techniques of each kind and their combination, with the ultimate goal of improving software and system dependability.