The current study examined the role that resiliency and diabetes quality of life play in school functioning and glucose control among adolescents with diabetes. Participants included 45 adolescents with diabetes who participated in a larger study evaluating the feasibility of a model of mental health screening, assessment, and referral/service coordination. We hypothesized that aspects of resiliency (e.g., self-mastery, optimism, interpersonal relations, emotional control) would be related to self-reported grades and glucose control Hemoglobin A1c (HbA1c). We also hypothesized that the relation between resiliency and HbA1c would be mediated by blood glucose monitoring. We found that self-mastery (i.e., the perception that one has the ability to overcome challenges and solve problems) predicted self-reported school grades. Fewer diabetes-related worries and parental reports of less school-related problems (e.g., absences, problems with teacher) also predicted better grades. Females and youth with less disruptive behaviors and higher levels of self-mastery were less likely to be viewed by parents as having problems in school. Self-mastery, in addition to later age of onset and more frequent blood glucose monitoring, predicted lower HbA1c. The mediational model could not be tested because the same components of resiliency that related to blood glucose monitoring did not relate to HbA1c. This study suggests that evaluation of positive attributes of adolescents, particularly the self-mastery component of resiliency, and consideration to the adolescents' perceptions of how diabetes affects their lives, may assist in understanding how these adolescents perform in school and manage their diabetes.