Although the detrimental role of adolescent triangulation into interparental conflict on their adjustment is well documented, the possible intervening mechanisms have not been fully investigated. Guided by the self-determination theory, we aimed to examine the mediating role of needs frustration in the relationship between adolescent triangulation and adjustment, namely depressive feelings and subjective vitality. Participants were 461 Turkish high school students (M-age = 17.25, SD = 1.16; 64.21% females). Triangulation subscale of the Children's Perception of Interparental Conflict Scale was used to measure the triangulation perception of adolescents, Basic Needs Frustration subscale of the Basic Psychological Need Satisfaction and Frustration Scale was used to measure adolescent needs frustration, Center for Epidemiologic Studies-Depression Scale, and Subjective Vitality Scale were employed to assess adolescent adjustment. The results of the path analysis showed that triangulation related positively to needs frustration, which in turn, positively predicted depressive feelings and negatively predicted subjective vitality. These findings indicated the significant intervening role of needs frustration in the relationship among adolescent triangulation, depressive feelings, and subjective vitality. The discussion focuses on the findings and implications for the familial and individual determinants of adolescent adjustment in the context of the self-determination theory and the potential avenues for future research.