This study aimed to explore whether beliefs about willpower are associated with emotional well-being. A cross-sectional study of 323 people with type 2 diabetes completed a short form of the Problem Areas In Diabetes Scale and the World Health Organisation five-item well-being scale, the Brief Illness Perceptions Questionnaire for diabetes (BIPQ) and the Implicit Willpower Beliefs to Resist Temptations (IWB-RT). A total of 332 individuals responded. They were a mean of 61.3 (SD 11.8) years of age, 68% were from the UK, 41% were female, and 30% had completed secondary education. They had diabetes for a mean of 10.0 years (SD 8.6), with 78% taking oral antidiabetes medication, 26% taking insulin, 71% taking medication for their blood pressure and 71% taking medication for their cholesterol. After controlling for demographics, treatment characteristics and illness beliefs, holding a resource limited belief about the nature of willpower was associated with reporting higher levels of diabetes distress. These results indicate that holding a resource limited belief about the nature of willpower may be a predisposing factor contributing to the development of diabetes distress. Longitudinal and experimental studies are required to confirm this possible causative role for willpower beliefs in the aetiology of diabetes distress.