This book constitutes the proceedings of the 17th International Conference on Foundations of Software Science and Computation Structures, FOSSACS 2014, held as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2014, which took place in Grenoble, France, in April 2014. The 28 papers included in this book, together with one invited talk, were selected from 106 full-paper submissions. The following topical areas are covered: probabilistic systems, semantics of programming languages, networks, program analysis, games and synthesis, compositional reasoning,...