The Indonesian government's deradicalization program, which was developed and implemented using both a complex and a gentle approach, was not optimal. The government requires mass organizations such as Nahdlatul Ulama and Muhammadiyah's involvement in overcoming radicalism through collaborative governance. The purpose of this study is to define the roles of Nahdlatul Ulama and Muhammadiyah and to analyze their positions from the perspective of collective governance. This qualitative research drew on two distinct types of data sources: primary and secondary. By collecting these types of data, we became the primary instruments in this study. The data were then analyzed using content analysis techniques to arrive at the following conclusion: 1) As members of civil society, Nahdlatul Ulama and Muhammadiyah are critical in preventing radicalism because they comprehend Ahlussunnah wal Jama'ah, the code of conduct that all of Islam's adherents adhere to in order to demonstrate Islam's peaceful face. Nahdlatul Ulama and Muhammadiyah also use their organizational structure, movement, and responsiveness to various issues to combat radicalism. Additionally, the educational network of Islamic boarding schools, regular schools, madrasas, and universities under two has developed into a breeding ground for the moderate Islamic generation; 2) Although Nahdlatul Ulama and Muhammadiyah have participated in various government-sponsored programs, this has not yet been classified as government collaboration.