The paper analyses Open budget and Participatory budgeting policies and practice of five post-Soviet countries (Russia, Belarus, Kazakhstan, Armenia, and Kyrgyzstan) belonging to the Eurasian Economic Union. We involve the assessment of current situation in these countries by international organizations. We find out the value and effectiveness of the legal base on Open budget and Participatory budgeting of each analyzed country and explore the 'zone of competence' in implementation the corresponding legislation. We analyze the models of participatory budgeting which are specific for Eurasian Economic Union countries.