Citizens’ active participation using information and communication technology (ICT) enables government harnessing social media to provide information and seek public interactions and collaborations. This research conducted a case study in the Ministry of Foreign Affairs (MoFA) of the Republic of Indonesia, which has strategic goals to achieve open government by utilizing digital diplomacy. This study aims to measure the maturity level of open government in the ministry, by focusing on the application of social media and giving recommendation for further implementation. To collect the data, this investigation employed qualitative research by conducting semi-structured interviews with officials working on digital diplomacy, observation, and gathering relevant data. The result shows that ministry maturity level in the application of social media using a combined framework of the Open Government Maturity Model (OGMM) and Open Government Implementation Model (OGIM) is at level 1 (initial condition). To advance data reliability, effective access, and improve the maturity level, the ministry is recommended to better manage the data governance.