ENEngaging active citizenry in public policy decisions using participative and collaborative processes is increasingly recognized as a critical step in implementing the open government concept. In this paper, we examine challenges and success factors as well as specific instruments and good practices in implementing participatory and collaborative governance in different governance contexts. Drawing on a comparative analysis of the approach adopted for the development and implementation of long-term strategies in Lithuania and Finland, we specifically focus on institutionalization of participative and collaborative processes along the policy-making cycle. The findings suggest that the most serious challenges associated with transitioning from ‘old’ to ‘new’ governance modes can be expected in countries associated with classical bureaucracy and legalistic institutional culture. In particular, such systems create internal and external pressure to focus on outputs as proof of results, which often trump efforts to enhance learning and consensus-building. Lessons learned from "Finland 2030" and "Lithuania 2030" suggest that institutionalization through leadership, clear responsibilities, a wide consensus within the society and administrations, and permanent stakeholder involvement platforms, is crucial to enable cultural change. The paper proposes a participative and collaborative governance maturity model that could be applied for benchmarking countries or policies. Keywords: Open government; Participative governance; Collaborative governance, Co-creation; Citizen involvement; Institutionalization. [From the publication]