This book constitutes the thoroughly refereed conference proceedings of the Third International Workshop on Risk Assessment and Risk-driven Testing, RISK 2015, held in conjunction with the OMG Technical Meeting in Berlin, Germany, in June 2015. The revised 8 full papers were carefully reviewed and selected from 12 submissions. This workshop addresses systematic approaches that combine risk assessment and testing. Also, the workshop was structured into the three sessions namely Risk Assessment, Risk and Development and Security Testing.