Background: Management of T1D requires processes of EF such as planning, problem-solving, and task-completion. This study examined associations of EF with T1D management and outcomes in teens with T1D. Methods: Teens and their parents completed self-report and parent proxy-report versions, respectively, of the Behavior Rating Inventory of Executive Function (BRIEF). Scores ≥60, as total (Global Executive Composite [GEC]) score or on 2 indices (Behavioral Regulation [BRI] and Metacognition [MI]) indicate EF problems. Parents completed validated surveys assessing teen adherence, teen T1D self-efficacy, parent involvement in T1D care, and diabetes-specific family conflict. Results: The sample (N=169, 54% male) was 15.9±1.3 (M±SD) years old and had T1D for 8.4±3.7 years; 67% were pump treated, A1c was 8.5±1.2%. Parent reported vs. teen reported GEC scores uncovered 25% vs. 9% of teens with EF problems (p<.001). Teens with EF problems (GEC, BRI, MI) by parent proxy-report were less likely to use pump therapy and had higher A1c, poorer adherence, lower T1D self-efficacy, more parent involvement, and greater family conflict (Table). Conclusions: Parents appear to be more likely than teens to identify teen EF problems. Screening for executive dysfunction in teens with T1D should be considered in order to identify teens in need of family and healthcare team support. Disclosure M. Hansmann: None. Z. Guo: None. L. Volkening: None. L.M. Laffel: Consultant; Self; Eli Lilly and Company, Novo Nordisk Inc., Sanofi US, MannKind Corporation, Roche Diagnostics Corporation, Dexcom, Inc., Insulet Corporation, AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Johnson & Johnson Diabetes Institute, LLC..