This longitudinal study examined coparenting and child adjustment during early and middle childhood (Ms = 3 and 8 years, respectively) among 106 lesbian, gay, and heterosexual parent adoptive families. When children were in middle childhood, no differences emerged as a function of parental sexual orientation in observations or self-reports of coparenting; in addition, parents and teachers described children as well-adjusted overall. After controlling covariates, including couple relationship adjustment, more supportive coparenting in early childhood predicted fewer parent-reported child internalizing and externalizing problems in middle childhood. Within middle childhood, stronger parenting alliance was associated with fewer parent-reported child externalizing problems. These findings indicate the value of considering family processes among diverse families in contributing to child outcomes over time.