One of the most pressing tasks facing policymakers in the 21st century is reducing stark group‐based inequalities that have developed within many societies because of centuries of structural discrimination. However, efforts to redress group disparities through equality‐promoting policies are frequently met with policy backlash and countermobilization. We describe several social psychological contributors to policy backlash, distinguishing between identity‐based and ideology‐based processes. While the role of identity politics in driving support and opposition to policies pertaining to race, gender, and sexual orientation is well‐known, less attention has been given to the role of ideological motivation, including individual and group differences in system justification tendencies to defend and bolster the societal status quo. In this article, we develop a framework based on system justification theory to understand why backlash against equality‐promoting policies occurs, when such backlash is most likely to occur, and who is most likely to be countermobilized against such policies. From this perspective, policy backlash is motivated not only by the desire on the part of advantaged group members to maintain their own existing privileges but also by the broader desire to maintain the perceived legitimacy and stability of the overarching social system. We make recommendations about how leaders can develop and communicate about equality‐promoting policies in a way that reduces the likelihood of backlash due to system justification motivation.