Programming Languages and Systems : 29th European Symposium on Programming ESOP 2020 Held as Part of the European Joint Conferences on Theory and Practice of Software ETAPS 2020 Dublin Ireland April 25–30 2020 Proceedings This open access book constitutes the proceedings of the 29th European Symposium on Programming ESOP 2020 which took place in Dublin Ireland in April 2020 and was held as Part of the European Joint Conferences on Theory and Practice of Software ETAPS 2020. The papers deal with fundamental issues in the specification design analysis and implementation of programming languages and systems. .