This special issue contains revised and extended versions of papers presented at the 20th European Symposium in Programming (ESOP'11), held in Saarbrucken, Germany, during March 26-April 3, 2011, as part of the Joint European Conferences on Theory and Practice of Software (ETAPS).

The papers collected in this special issue have been invited by the guest editors based on conference reviews, and have been reviewed in accordance with the usual high standards of LMCS. We are grateful to the authors and to the reviewers of ESOP'11 and of this special issue for their excellent work. The result is a collection of nine papers that cover a representative range of topics in the scope of ESOP: concurrency, security, probabilistic programming, program analysis, program verification, proof assistants. Happy reading!