This book constitutes the proceedings of the 17th International Conference on Developments in Language Theory, DLT 2013, held in Marne-la-Vallée, France, in June 2013. The 34 full papers presented in this volume were carefully reviewed and selected from 63 submissions. The scope of the conference includes, among others, the following topics and areas: combinatorial and algebraic properties of words and languages; grammars, acceptors and transducers for strings, trees, graphs, arrays; algebraic theories for automata and languages; codes; efficient text algorithms; symbolic dynamics; decision problems; relationships to complexity theory and logic; picture description and analysis; polyominoes and bidimensional patterns; cryptography; concurrency; cellular automata; bio-inspired computing; and quantum computing.