This study investigated the correlations between health-related quality of life and social support in adolescents with type 1 diabetes (T1DM). Participants were 102 adolescents between 12 and 17 years old, who were patients of a healthcare program in the city of Porto Alegre, south of Brazil. Two questionnaires, the KIDSCREEN-52 and the Brazilian version of Social Support Appraisals, were used to evaluate health-related quality of life and social support. Results showed good quality of life and social support levels. Strong correlations were verified between social support and three of the KIDSCREEN-52 dimensions: psychological well-being (r = .63; p < .01); peers and social support (r = .67; p < .01) and school environment (r = .64; p < .01). Analysis of linear regression showed that gender, age and social support are variables associated with health-related quality of life, explaining 52.6% of variance. Results revealed the impact of the disease to young people, and can help to find strategies to improve care in these cases.