Due to high profile police shootings, collective action movements addressing racial bias in policing, such as the Black Lives Matter (BLM) movement, have come to the forefront of societal concern. Though these movements and actions directly address police use of force against Black people, a number of non-Black racial minority individuals and organizations have declared solidarity and joined in protests with BLM. This study takes an intersectional approach to examine racial intraminority attitudes (i.e., racial minorities' attitudes toward other racial minority outgroups) toward support for and participation in protests against police excessive use of force and the BLM movement, through its relationship with modern racist beliefs and racial centrality. Participants completed a survey assessing perspectives on policing, racial protests, and BLM, along with racial identity measures. Results show significant differences in both support for and participation in protests and BLM, with women and Black people reporting higher in both outcomes than men and other racial groups, respectively. Within some racial groups, women show higher overall support for (Latinx, White) and participation in (Black, White) protests and BLM than men in the same racial group, though these differences were not found for other groups. Within each intersecting race and gender group, these effects were mediated by levels of modern racism, highlighting a common factor between all groups and an important point of possible malleability and intervention. Further, the relationship between race and gender identities and modern racism was moderated by racial centrality for some groups (Black and Latina women), though this relationship was again not universally found. By examining within group differences, this study highlights the importance of taking an intersectional approach to understand intraminority attitudes and relations as they pertain to participation in collective action movements towards social change. This study has implications for the generalizability of a number of social psychological theories on minority-minority intergroup race relations (i.e., Black-Latinx), as much of the past literature focuses on majority-minority intergroup relations (i.e., Black-White). Additionally, results from this study may provide useful information for community organizers and social justice activists in promoting intergroup collaboration and coalition building towards more equitable social change that is both more tailored for specific groups and more generalizable across groups.