The use of innovative digital technologies enables public sector organizations to collect information and knowledge from citizens and other interested parties and consequently use these inputs to create new, better and more efficient public policies and services and to be better at decision-making. The role of local government is particularly important in the public life of citizens, given the more frequent and intimate relationship with citizens compared to the central and regional authorities. For this reason, local authorities have the responsibility to facilitate interaction with the local community and enable various mechanisms of participation, which is essential in economic and social development. The availability of e-participation tools and services is important for expressing the needs of the local community, as well as for providing feedback on local government practices, policies and services. E-participation strengthens the responsibility of public bodies by making public services and policies more sensitive to the needs of citizens. In order to understand how local governments decide to adopt an innovation in the form of e-participation, this paper has identified factors that influence the adoption of e- participation. Through research with experts, the measuring items of the researched factors were defined and the research instrument was formed. A conceptual model of e-participation adoption is developed using TOE framework, organisational theory that considers technological, organizational and environmental factor that influence the adoption of certain innovation. The main research included 248 respondents, heads of administrative departments from 81 local governments in the Republic of Croatia. The assessment of the structural model for measuring the association of the proposed TOE factors with the adoption of e-participation was made using the method of partial least squares structural equation modeling (PLS-SEM). The research results confirmed the importance and relation of ICT infrastructure, top management support, human resources expertise, pressure from city/municipal stakeholders and citizens' readiness to adopt e-participation in local governments. The size of city/municipality proved to be important in identifying the differences between small and large cities in perceiving benefits from e-participation and for ICT infrastructure.