["Corporate Social Responsibility and Environmental Management, EarlyView. ", "\nABSTRACT\nState‐owned enterprises (SOEs) are hybrid organizations that pursue social and economic goals and are expected to engage in sustainability reporting. Previous literature has shown limited attention to examining the process by which a norm in sustainability reporting has emerged among SOEs. To fill this research gap, we provide a historically informed analysis of how sustainability reporting has evolved into a standard practice in Spanish SOEs. To achieve our goals, we employed a qualitative research method that utilized two primary data sources: interviews and corporate annual reports published between 2005 and 2020. Our findings suggest that sustainability reporting has become a norm for Spanish SOEs due to two interconnected factors. First, the participation of key institutional actors in developing and consolidating sustainability reporting. Second, the existence of specific conditions that facilitated the creation of a sustainability reporting norm. By using the notion of normativity, this study contributes to the existing literature by examining the dynamics, actors, and conditions that led to sustainability reporting becoming a norm within Spanish SOEs. Our results imply that the configuration of a norm depends more on the influence of multiple actors than on the regulatory role exercised by state actors.\n"]