Previous research in families of children with type 1 diabetes demonstrates that maternal depressive symptoms are a known risk factor for poor diabetes outcomes. We sought to examine whether maternal diabetes relationship distress or maternal depressive symptoms were more strongly associated with adolescent glycemic outcomes. Analyses were conducted using data from mothers who consented to screen for a behavioral intervention. The screener included the Patient Health Questionnaire and the Parent Diabetes Distress Scale, Parent/Teen Relationship Distress subscale. Hemoglobin A1c (HbA1c) was extracted from adolescents' medical records. Our sample consisted of 390 maternal caregivers of adolescents with type 1 diabetes aged 11-17. Screening data revealed that 35% of mothers reported clinically significant diabetes distress related to their relationship with their adolescents, and 14% of mothers reported clinically significant depressive symptoms. The adolescents of mothers who reported diabetes relationship distress had significantly higher mean HbA1c levels (9.7 ± 2.2%) compared to those whose mothers were not distressed (8.2 ± 1.8%, d = .72). Similarly, adolescents whose mothers reported clinically significant depressive symptoms had higher mean HbA1c levels (9.6 ± 2.4%) than those whose mothers were not depressed (8.6 ± 2.0%, d = .48). After adjusting for clinical and demographic factors, mothers' reports of diabetes relationship distress were more strongly associated with adolescents' HbA1c than maternal depressive symptoms. Our findings suggest that screening for maternal distress-particularly distress related to the caregiver-adolescent relationship-could match families with psychosocial support or other resources to improve both psychosocial and glycemic outcomes.