Insulin omission is a serious concern for those with type 1 diabetes (T1D), predicting subsequent complications and mortality. It is, thus, imperative to understand factors that may elevate insulin omission, especially during late adolescence when risk behaviors are increasing and T1D management is low. We examined how two interrelated factors – emotion dysregulation and depressive symptoms – may be related to insulin omission during late adolescence. A mediation model examined whether emotion dysregulation was associated indirectly with insulin omission through enhanced depressive symptoms, as has been shown in prior disordered eating literature. A moderation model examined whether emotion dysregulation exacerbated associations of depressive symptoms with insulin omission. Seniors in high school with T1D longer than one year (N = 236) completed measures of depressive symptoms, difficulties in emotion regulation (DERS), and diabetes self-management behaviors, as well as a one-item measure of insulin omission for the purpose of losing weight, and a mail-in assay kit to assess HbA1c. Consistent with prior research, most participants reported they never skip insulin to lose weight, but 39 (17%) reported they skip insulin for the specific purpose of losing weight at least some of the time. Individuals who indicated they sometimes skip insulin to lose weight had higher (poorer) HbA1c than those who never skip insulin, M = 8.94 vs 8.14%, which is a clinically meaningful difference. Each of the six DERS subscales and depressive symptoms were individually correlated with greater insulin omission (rs > .140). Logistic regressions in MPLUS were utilized to examine whether DERS subscale scores were associated with insulin omission both directly, as well as indirectly through greater depressive symptoms. This mediation model was supported, as the indirect path through depressive symptoms was significant for each facet of emotional dysregulation on insulin omission. Tests of moderation revealed no significant interactions between depressive symptoms and DERS subscales, suggesting that depressive symptoms pose risks for insulin omission even among those with good emotion regulation skills. Programs to develop emotion regulation skills and minimize depressive symptoms, and screening for insulin omission especially among those with elevated depressive symptoms may be helpful at this high-risk time of development.