This book constitutes the thoroughly refereed proceedings of the 21st International Symposium on Static Analysis, SAS 2014, held in Munich, Germany, in September 2014. The 20 revised full papers were selected from 53 submissions and are presented together with 3 invited talks. The papers address all aspects of static analysis, including abstract interpretation, abstract testing, bug detection, data flow analysis, model checking, program transformation, program verification, security analysis, and type checking.