This book constitutes the proceedings of the 6th International Conference on Concurrency Theory, CONCUR '95, held in Philadelphia, Pennsylvania in August 1995. The volume presents seven invited contributions by outstanding researchers and 33 refereed full research papers selected by the program committee out of a total of 91 submissions. The collection of articles gives a representative overview on what happened in this area of research, since the last CONCUR conference took place. There are sections on model checking, mobile processes, process theory, true concurrency, process algebra, probabilistic automata, real-time systems, testing semantics, decidability results, refinement theory, and linear-time logics.