Prior scholarship suggests that variation in neighborhood ethnic–racial compositions may be predictors of cultural developmental processes and experiences for adolescents of color. Specifically, neighborhood ethnic–racial concentration may support or inhibit ethnic–racial identity (ERI) development or content; it may amplify or mitigate exposure to discrimination stemming from racism. It is important to consider factors that may explain mixed findings given study, neighborhood, and adolescent characteristics may be sources of systematic heterogeneity. A systematic review was conducted to examine the effects of neighborhood ethnic–racial concentration on discrimination and ERI among Black, Asian American, and Latinx adolescents. The search initially retrieved 162 records; 13 met inclusion criteria and were coded for theoretical and design elements. A total 36 associations were identified (discrimination: k = 16; ERI: k = 20). For discrimination, a majority of the associations (56%) were in the promoting direction, such that higher neighborhood ethnic–racial concentrations of Blacks, Asian Americans, and Latinxs were associated with less discrimination for Black, Asian American, and Latinx adolescents, respectively. For ERI, 35% of the associations were promoting, such that higher neighborhood ethnic–racial concentrations of Blacks, Asian Americans, and Latinxs were associated with more positive ERI outcomes for the same groups. Almost all of the remaining findings for discrimination were null (38%) and all remaining findings for ERI (65%) were null. This systematic review documents how higher neighborhood ethnic–racial concentrations are potentially beneficial to within-group adolescents navigating the development of ERI and discrimination.