This book constitutes the proceedings of the 13th IFIP WG 8.5 International Conference on Electronic Participation, ePart 2021, held in Granada, Spain, in September 2021, in conjunction with IFIP WG 8.5 Electronic Government (EGOV 2021), the Conference for E-Democracy and Open Government Conference (CeDEM 2021).

Digital Participation.- Youths' digital participation in the early phases of COVID-19 lockdown.- Discovering Sense of Community enabling factors for Public and Government Staff in Online Public Engagement.- Understanding civic engagement on social media based on users' motivation to contribute.- Digital Society.- Researching Digital Society: Using Data-Mining to Identify Relevant Themes from an Open Access Journal.- Whose Agenda Is It Anyway? The Effect of Disinformation on COVID-19 Vaccination Hesitancy in the Netherlands.- A conceptual model for approaching the design of anti-disinformation tools.- User needs for a mobility app to support living in rural areas.- Adoption of E-Government Requirements to Higher Education Institutions Regarding the Digital Transformation.- Digital Government.- Developing Cross-border E-governance: Exploring Interoperability and Cross-border Integration.- Accountable Federated Machine Learning in Government: Engineering andManagement Insights.- Agile Development for Digital Government Services: Challenges and Success Factors.- Data-driven Personalized E-government Services: Literature Review and Case Study.- Legal Issues.- Application of process modelling and simulation to evaluate administrative burdens at the law-making stage.- Evaluating Second Generation Cross-Country Open Legal Data Infrastructures Using Value Models.- Analysing the implementation of electronic communication strategies through legislation.- The accountability of intelligence and law enforcement agencies in information search activities.