OBJECTIVE: To examine inequality in glycemic control by maternal educational level among children with type 1 diabetes in a setting with universal access to health care. RESEARCH DESIGN AND METHODS: This was a longitudinal nationwide study of 4,079 Danish children with type 1 diabetes between the years 2000 and 2013. Children were divided into four groups based on mothers' education prebirth (≤high school [n = 1,643], vocational or 2-year college [n = 1,548], bachelor's degree [n = 695], ≥master's degree [n = 193]). Means of socioeconomic and treatment characteristics were compared between groups. HbA1c and the number of daily glucose tests were compared repeatedly from onset until 5 years after onset across groups. HbA1c was compared across daily blood glucose testing frequency and groups. Linear regression was used to compare HbA1c across groups with and without adjustment for socioeconomic and treatment characteristics. RESULTS: Large differences in HbA1c across maternal education were found. The mean level of HbA1c during follow-up was 59.7 mmol/mol (7.6%) for children of mothers with ≥master's degrees and 68.7 mmol/mol (8.4%) for children of mothers with ≤high school (difference: 9.0 mmol/mol [95% CI 7.5, 10.6]; 0.8% [95% CI 0.7, 1.0]). The associations were attenuated but remained significant after adjustment. Observable characteristics explained 41.2% of the difference in HbA1c between children of mothers with ≤high school and mothers with ≥master's degree; 22.5% of the difference was explained by more frequent blood glucose monitoring among the children with the highly educated mothers. CONCLUSIONS: Family background is significantly related to outcomes for children with type 1 diabetes, even with universal access to health care.