--- - |2 This study examined the degree to which internalizing symptoms predict adolescent friendship instability. A total of 397 adolescents identified 499 same‐sex reciprocated friendships that originated in the seventh grade (M = 13.18 years). Discrete‐time survival analyses were conducted with Grade 7 peer, teacher, and self‐reports of internalizing symptoms as predictors of friendship dissolution across Grades 8–12. Differences between friends in depressive symptoms, anxiety symptoms, and (for boys only) submissiveness predicted subsequent friendship dissolution. Individual levels of these variables did not predict friendship dissolution, even at extreme or clinical levels. The findings suggest that friendship instability arising from internalizing problems stems from dissimilarity between friends rather than the presence of psychopathological symptoms on the part of one friend. - Journal of Research on Adolescence, EarlyView.