School-based, universal social and emotional learning (SEL) has been widely practiced and promoted as a promising approach to prevent youth mental, emotional, and behavioral problems. Although prior research has accumulated robust evidence of the average effects of universal SEL, it remains unclear whether it works similarly or differentially across diverse sociocultural subgroups of students. Investigating subgroup effects has implications for understanding the impact of universal SEL on possible subgroup disparities in student social-emotional competence (SEC). This study examined whether the effects of a universal SEL program on student SEC development differed across diverse student subgroups classified by gender, race, ethnicity, socioeconomic status, disability status, and English learner status. Data came from student SEC progress monitoring collected during a 1-year quasi-experimental study of a universal SEL program (N?=?1592; Grades K?2). The results of multigroup latent growth modeling suggest that (a) the intervention effects were slightly larger for Black students, compared to White or other racial-ethnic subgroups, and (b) the effects were not different across other examined subgroups. This study also found that in the comparison condition, the SEC disparities between Black and White students tended to widen throughout the year, whereas in the intervention condition, Black students showed a similar rate of growth as their White peers. Findings suggest that universal SEL may be similarly beneficial across many diverse student subgroups, while it may yield larger benefits among some racially marginalized subgroups, preventing racial disparities from further widening. Yet the benefits of SEL may not be sufficient to reduce existing subgroup disparities. These findings suggest a need for more studies to examine differential effects of universal preventive programs by diverse subgroups to better inform practices that enhance equity in youth outcomes.