This book constitutes the refereed proceedings of the 15th IFIP WG 8.5 International Conference on Electronic Government, EGOV 2016, held in Guimaraes, Portugal, in September 2016, in conjunction with the 8th International Conference on eParticipation, ePart 2016. The 24 revised full papers presented were carefully reviewed and selected from 87 submissions. The papers are clustered under the following topical sections: foundations; benchmarking and evaluation; information integration and governance; services; evaluation and public values; EGOV success and failure; governance; social media; engagement; processes; policy-making; trust, transparency and accountability; open government and big/open data; smart government/governance/cities.