Muslim school is an important element of education in Indonesia. The school has been in place long time before Indonesia’s independence in 1945. The school educates Indonesian Muslim children to understand and practice religion, and simultaneously, promotes the sense of nationalism. Thanks to Muslim schools, Indonesian Muslims are recognized as being moderate (Hefner, 2000). In the last few years, however, the moderate nature of Indonesian Islam is challenged by the spirit of conservative Islam (Van Bruinessen, 2013). Issues such as Islam and democracy, Islam and modern state, Muslim and non-Muslim relation, and rights of citizen that have been resolved and agreed upon are being reinstated. As Hefner (2007) argues that there is a relationship between politics and education, especially religious education, it is important to see the relationship between schools and the changing society. The question is how the current conservative trend in Indonesian Islam is occurring at schools. This paper explores how the curriculum of (Islamic) religious education potentially contribute toward the development of Indonesian conservative Islam, and how religious education teachers view sensitive issues concerning conservative Islam. To answer the questions, analysis of religious education’s curricula and interviewing experts serve as the primary method of data collection. Four religious education teachers from different provinces of Indonesia were interviewed to reveal their opinions on various religion-related issues. This paper discusses how Islamic education in Indonesia has been designed to present moderate Islam, but at the same time faces a number of challenges that try to turn religious education into a conservative one.