This book constitutes the refereed proceedings of the 24th IFIP WG 6.1 International Conference on Testing Software and Systems, ICTSS 2012, held in Aalborg, Denmark, in November 2012. The 16 revised full papers presented together with 2 invited talks were carefully selected from 48 submissions. The papers are organized in topical sections on testing in practice, test frameworks for distributed systems, testing of embedded systems, test optimization, and new testing methods.