The ACM SIGPLAN Conference on Software Language Engineering (SLE) is devoted to the principles of software languages: their design, their implementation, and their evolution. SLE 2015 will be held on October 26 & 27 2015, co-located with SPLASH, OOPSLA and GPCE 2015 in Pittsburgh, USA. SLE workshops will be held before the conference on the 25th of October. Proposals for SLE workshops should be submitted to the SPLASH workshop process, and should be clearly labelled as “affiliated with SLE”. SLE’s mission is to fuse several communities that have traditionally looked at software languages from different and yet complementary perspectives: programming languages, model driven engineering, domain specific languages, semantic web, and from different technological spaces: context-free grammars, object-oriented modeling frameworks, rich data, structured data, object-oriented programming, functional programming, logic programming, term-rewriting, attribute grammars, algebraic specification, etc.