For civil servants in the legal sector, the best performance that must be shown is not how they carry out activities following standard operational procedures but what is more important is how they show Organizational Citizenship Behavior (OCB) in daily activities. This study aims to examine what factors influence the formation of OCB civil servants in the legal sector in Indonesia. The study was conducted on 145 civil servant respondents who were involved in secretarial activities, each from the Judicial Commission Secretariat, the Attorney General’s Office, the Ministry of Justice, the Supreme Court, the Police Headquarters, and the Constitutional Court. The research methodology used Partial Least Square (PLS) Version 3.0. The empirical findings of the research show that organizational culture has a significant influence in shaping transformational leadership that can build OCB among civil servants in Indonesia. This effect is much larger and more significant than the compensation system, which is widely believed to be the main factor in forming OCB, such as the results of previous studies. The results of this study imply that the formation of an organizational culture with values that can create high work productivity which has an impact on transformational leadership styles in building OCB.