Introduction: Young adults (YAs) with T1D experience poorer self-care, psychosocial well-being and clinical outcomes relative to other age groups. A better understanding of factors that drive these challenges is needed to better support this age group. Behavioral science theory suggests that greater autonomous (vs. controlled) motivation (the degree to which behaviors are motivated by internal vs. external drivers) may enable YA to more effectively navigate the challenges of living with T1D. Methods: Baseline surveys and clinical data from an ongoing self-management RCT were analyzed to examine associations between autonomous motivation (modified TSRQ) , glycemic control (HbA1c) , diabetes distress (DDS) , diabetes self-management (DSMQ) , self-efficacy (DES-SF) , and quality of life (ADD-QoL) . All analyses were adjusted for treatment regimen (injections/pump/CGM) . Results: Among 133 YA with T1D (24.2±3.7 yrs, 53% female, 53% Latinx, 36% White, 11% multiethnic/other) , more autonomous motivation was associated with lower diabetes distress (standardized b= -0.19, p=0.04) and better self-management (b=0.18, p=0.04) . Analyses revealed that the association of autonomous motivation with lower diabetes distress scores was attributable to its associations with the emotional burden (b=-0.17, p=0.05) and regimen distress (b=-0.24, p=0.01) subscales, and its association with higher self management scores was driven by its association with the glucose monitoring subscale (b=0.32, p=0.0005) . Relationships between motivation and other measures were not significant. Conclusion: Among YA with T1D, those with greater autonomous motivation for diabetes care had lower regimen distress and emotional burden, and greater glucose monitoring. While the causal direction of these relationships is unclear, it is plausible that interventions to enhance autonomous motivation may enhance self-management and well-being in this population. Disclosure E.Pyatak: Research Support; Abbott Diabetes. E.Taylor: None. J.Raymond: None. C.Vigen: n/a. J.Sideris: None. D.Fox: None. J.Diaz: None. A.Ali: None. J.Blanchard: None. G.Granados: None. E.Salazar: None. Funding National Institutes of Health (R01DK116719)