Teens with type 1 diabetes (T1D) experience increased sleep disturbances, which have been linked to problems with adherence and glycemic control. As such, sleep represents a novel target to improve outcomes in teens. To evaluate the feasibility, acceptability, and preliminary efficacy of a sleep-promoting intervention in teens with T1D. Teens aged 13 to 17 with T1D (n = 39) completed measures of sleep quality and diabetes management and wore actigraphs to obtain an objective measure of sleep. Hemoglobin A1C (HbA1c) was collected from medical records. Teens were randomized to Usual Care (n = 19) or the Sleep Coach intervention (n = 20). Teens in the Sleep Coach group received educational materials on healthy sleep habits and completed three individual telephone sessions. Follow-up data were collected at 3 months, including exit interviews with teens and parents. Feasibility of the study was excellent; 80% of teens in the Sleep Coach group completed all three sessions, and retention was high (90%). Based on actigraphy data, a significant improvement in sleep efficiency and sleep duration was observed (48-minute increase) among teens randomized to the Sleep Coach intervention, and teens in the control group were 7.5 times more likely to report poor sleep quality after 3 months than intervention participants. No change in HbA1c was observed. The Sleep Coach intervention for teens with T1D is a feasible and acceptable program that increased sleep duration and improved sleep quality for this high-risk population.