This book constitutes the refereed proceedings of the 27th International Symposium on Static Analysis, SAS 2020, held in Chicago, IL, USA, in November 2020.The 14 regular papers presented in this book together with 2 invited talks and 1 extended abstract, were carefully reviewed and selected from 34 submissions. The papers cover topics such as abstract domains; abstract interpretation; automated deduction; data flow analysis; debugging; deductive methods; emerging applications; model-checking; program transformations; predicate abstraction; security analysis; tool environments and architectures; and type checking. Due to the Corona pandemic this event was held virtually.