This study evaluated whether young adult romantic relationship quality is an intergenerational mechanism linking Generation 1–2 (G1–G2) family climate and G2 social problem-solving skills during adolescence to G2–G3 parenting and family level-functioning and ultimately G3 child maladjustment and social–emotional competence. Our sample included 396 families with a parent (Mage = 28.29; 94% White) from a longitudinal study starting when they were in 6th grade. Participants completed annual assessments through high school, three assessments in young adulthood, and surveys after becoming parents. Two intergenerational pathways emerged: Positive G1–G2 family climates in adolescence predicted less young adult relationship violence; in turn, violence was associated with lower G2–G3 harsh discipline, abusive parenting, and family conflict. Of these, harsh discipline and abusive parenting were associated with G3 children’s adjustment. In addition, G2 social problem-solving skills in adolescence were associated with stronger couple problem-solving skills in young adulthood and with better G2–G3 family routines; in turn, G2–G3 family routines were associated with G3 child social–emotional competence. Finally, moderation effects were observed in which youth who received the PROSPER interventions exhibited associations between adolescent social problem-solving skills and young adult couple problem-solving and G2–G3 parental warmth and (lower) lax discipline.