The current cross-cultural study aimed to extend research on parenting and children’s prosocial behavior by examining relations among parental warmth, values related to family obligations (i.e., children’s support to and respect for their parents, siblings, and extended family), and prosocial behavior during the transition to adolescence (from ages 9 to 12). Mothers, fathers, and their children (N = 1107 families) from 8 countries including 11 cultural groups (Colombia; Rome and Naples, Italy; Jordan; Kenya; the Philippines; Sweden; Thailand; and African Americans, European Americans, and Latin Americans in the United States) provided data over 3 years in 3 waves (Mage of child in wave 1 = 9.34 years, SD = 0.75; 50.5% female). Overall, across all 11 cultural groups, multivariate change score analysis revealed positive associations among the change rates of parental warmth, values related to family obligations, and prosocial behavior during late childhood (from age 9 to 10) and early-adolescence (from age 10 to 12). In most cultural groups, more parental warmth at ages 9 and 10 predicted steeper mean-level increases in prosocial behavior in subsequent years. The findings highlight the prominent role of positive family context, characterized by warm relationships and shared prosocial values, in fostering children’s positive development in the transition to adolescence. The practical implications of these findings are discussed.