This book constitutes the refereed proceedings of the 8th IFIP WG 8.5 International Conference on Electronic Participation, ePart 2016, held in Guimarães, Portugal, in September 5-8, 2016. The 14 revised full papers presented were carefully reviewed and selected from 31 submissions. The papers reflect completed multi-disciplinary research ranging from policy analysis and conceptual modeling to programming and visualization of simulation models. They are organized in four topical threads: theoretical foundations; critical reflections; implementations; policy formulation and modeling. .