This book constitutes the thoroughly refereed post-conference proceedings of the 6th IPM International Conference on Fundamentals of Software Engineering, FSEN 2015, held in Tehran, Iran, in April 2015.

The 21 full papers presented in this volume were carefully reviewed and selected from 64 submissions. The topics of interest in FSEN span over all aspects of formal methods, especially those related to advancing the application of formal methods in software industry and promoting their integration with practical engineering techniques.