Children's emotion knowledge encompasses abilities to recognize and label emotions in the service of positive adaptation. Drawing on a sociodemographically diverse sample of 250 children (50% female sex assigned at birth; Mage_W1 = 49.02 months, SD = 2.99) and their maternal caregivers (55.6% Latina; 37.6% poverty), this study evaluated a multiple mediation model to integrate heretofore distinct bodies of research examining (a) parenting effects on the development of emotion knowledge and (b) emotion knowledge effects on socioemotional adaptation. Observations of maternal supportive presence at age 4 predicted increases in children's emotion recognition and labeling from ages 4 to 8. However, only emotion labeling skills explained children's behavioral adjustment outcomes with a significant pathway from supportive parenting at age 4 to fewer externalizing and internalizing behavior problems at age 10 via improved emotion labeling skills. These findings suggest that emotion knowledge, particularly labeling skills, partially explains the protective impact of supportive parenting on behavioral adaptation across childhood. Prevention and intervention efforts should target both supportive parenting practices and emotion knowledge skill development to support children's socioemotional functioning and reduce behavior problems. (PsycInfo Database Record (c) 2024 APA, all rights reserved).