Inclusion Criteria:  T1D duration ≥6 months 18-30 years old HbA1c ≥8.5-14% English- or Spanish-speaking At least moderate DD (score of ≥2 on T1D-Diabetes Distress Scale) Stable insulin treatment regimen (insulin prescription, use of pump, etc.) for at least 3 months prior to study enrollment.  Exclusion Criteria:  Comorbid psychiatric condition, including depression, anxiety, or suicidality, which may be independently associated with the main outcomes of diabetes distress or glycemic control. Comorbid psychiatric conditions listed above are being excluded because CBT-DD currently centers on mitigating specifically diabetes distress to improve glycemic outcomes. Developmental or sensory disability interfering with participation Current pregnancy, as self-management and glycemic goals differ Participations in another behavioral intervention study Use of non-insulin medications or recent medical procedures that would impact glycemic control or use of CGM over the study.