Aims: The aim of this study was to investigate the relationship between diabetes stigma as experienced by adults with type 1 diabetes and diabetes outcomes using the novel, validated measure of the Type 1 Diabetes Stigma Assessment Scale. Methods: A total of 1594 adults with type 1 diabetes completed a questionnaire on socio-economic factors, psychosocial health, and diabetes stigma and these self-reported data were linked with data from electronic clinical records on glycaemic control, diabetes duration, age, and diabetes-related complications. Bivariate analyses and multivariate linear regressions were performed to assess the relationship between diabetes stigma as measured by three subscales, Identity concern, Blame and judgement, and Treated differently on the one hand, and patient characteristics and diabetes outcomes on the other. Results: Endorsement of the stigma statements ranged from 3.6-78.3% of respondents. Higher stigma scores in relation to Identity concern and Blame and judgement were significantly associated with being female, of lower age, lower diabetes duration, and having at least one complication. Those who reported higher levels of perceived stigma reported significantly higher levels of diabetes distress (β = 0.37 (95% CI: 0.33-0.40), 0.35 (95% CI: 0.30-0.39), 0.41 (95% CI: 0.35-0.46)), and HbA1c levels (β = 0.11 (95% CI: 0.02-0.21), 0.28 (95% CI: 0.16-0.40), 0.26 (95% CI: 0.14-0.42) for Identity concern, Blame and judgement, and Treated differently, respectively). Conclusions: The findings demonstrated that diabetes stigma is negatively associated with both diabetes distress and glycaemic control and should be considered part of the psychosocial burden of adults with type 1 diabetes.