This paper attempts to examine which factors explain public participation in the budget process in an international comparative approach. In particular, we investigate which socioeconomic, institutional, and political factors promote public engagement in the central government budget process. Using a sample of 93 countries, our results indicate that Internet penetration, population diversity, governmental financial situation, and budget transparency determine opportunities for public engagement in the central government budget process. In addition, we show that not only budget transparency promotes public participation but also public participation is necessary to enhance budget transparency. We examine which factors explain public participation in the budget process in an international approach. Internet, population diversity, governmental financial situation and budget transparency impact public engagement in the central government budget process. Not only budget transparency promotes public participation, but also public participation is necessary to enhance budget transparency.