This book constitutes the thoroughly refereed conference proceedings of the Fourth International Workshop on Risk Assessment and Risk-Driven Quality Assurance, RISK 2016, held in conjunction with ICTSS 2016, in Graz, Austria, in October 2016. The revised 9 full papers were carefully reviewed and selected from 11 submissions. They focus on research studying, developing and evaluating innovative techniques, tools, languages and methods risk assessment and risk-driven quality engineering. The papers are organized topical sections: security risk management; security risk analysis; risk-based testing.