The 15th International Symposium on Principles and Practice of Declarative Programming will take place in September 2013 in Madrid, Spain. PPDP 2013 is a forum that brings together researchers from the declaratrive programming communities, including those working in the logic, constraint and functional programming paradigms, but also embracing languages, database languages, and knowledge representation languages. The goal is to stimulate research in the use of logical formalisms and methods for specifying, performing, and analyzing computations, including mechanisms for mobility, modularity, concurrency, object-orientation, security, verification and static analysis. Papers related to the use of declarative paradigms and tools in industry and education are especially solicited.