This book constitutes revised selected papers from the Third International Workshop on Structured Object-Oriented Formal Language and Method, SOFL+MSVL 2013, held in Queenstown, New Zealand, in October 2013. The 13 papers presented in this volume were carefully reviewed and selected from 22 submissions. They are organized in topical sections on testing and verification, simulation and model checking, SOFL tools, and formal specification and application.