This book constitutes the proceedings of the 14th International Conference on Verification and Evaluation of Computer and Communication Systems, VECoS 2020, which was supposed to be held in Xi'an, China, in October 2020, but was held virtually instead. The 19 full papers and 1 short paper presented in this volume were carefully reviewed and selected from 60 submissions. The aim of the VECoS conference is to bring together researchers and practitioners in the areas of verification, control, performance, and dependability evaluation in order to discuss state of the art and challenges in modern computer and communication systems in which functional and extra-functional properties are strongly interrelated. Thus, the main motivation for VECoS is to encourage the cross-fertilization between various formal verification and evaluation approaches, methods and techniques, and especially those developed for concurrent and distributed hardware/software systems. The papers are organized in the following topical sections: petri-net, simulation, and scheduling; formal modeling and verification, testing; and artificial intelligence and machine learning.