In this study, we investigated trajectories of Black‐White biracial children's social development during middle childhood, their associations with parents’ racial identification of children, and the moderating effects of child gender and family socioeconomic status (SES). The study utilized data from parent and teacher reports on 293 US Black‐White biracial children enrolled in the Early Childhood Longitudinal Study‐Kindergarten Cohort (ECLS‐K). Growth curve models suggested increasing trajectories of teacher‐reported internalizing and externalizing behaviors between kindergarten and fifth grade. Parents’ racial identification of children predicted child externalizing behavior trajectories such that teachers rated biracially identified children's externalizing behaviors lower relative to those of Black‐ and White‐identified children. Additionally, for White‐identified biracial children, the effect of family SES on internalizing behavior trajectories was especially pronounced. These findings suggest that in the USA, how parents racially identify their Black‐White biracial children early on has important implications for children's problem behaviors throughout the elementary school years.