["Family Relations, EarlyView. ", "\nABSTRACT\n\nObjective\nTo understand family conflict and cohesion and adolescent mental health among families with and without child welfare involvement.\n\n\nBackground\nWhile the influence of cohesion and conflict on mental health is understood, the directionality of these relationships is challenging to disentangle. We examine family cohesion and conflict and internalizing/externalizing behaviors among a sample of families with and without child welfare involvement.\n\n\nMethod\nThe analyses include 329 caregiver–adolescent dyads who were part of a 10‐year longitudinal study. A path model was used to test the longitudinal and potential reciprocal effects among family conflict, family cohesion, and internalizing and externalizing symptoms.\n\n\nResults\nThere was a negative effect of family cohesion on internalizing symptoms, a positive effect of externalizing symptoms on conflict, a negative effect of internalizing symptoms on cohesion, and a positive effect of conflict on externalizing symptoms across varied timepoints. Higher cohesion was associated with lower scores on externalizing symptoms for the child welfare involved group; cohesion was negatively associated with externalizing symptoms for the comparison group. Cohesion and externalizing symptoms were significantly larger for males than females.\n\n\nConclusion\nFamily environment and adolescent mental health symptoms have a reciprocal association and change over time. These findings suggest the need for increased use of cognitive‐based family interventions that improve communication and problem‐solving skills within family systems.\n\n\nImplications\nThe promotion of family cohesion is critical for adolescent mental health.\n\n"]