Background  Previous studies have shown that Tourette syndrome (TS) has an impact on academic achievements. The aim of this study was to investigate the association between the severity of tics and comorbidities and educational outcomes. Methods  From 2005 to 2007, 395 participants were included in a large cohort (314 with TS and 81 controls) and the mean age was 12.60 ± 2.64 years. The cohort was re-examined after 4 to 8 years (median 5.6) where n = 276 participants (223 with TS and 53 controls) were included with a mean age of 18.52 ± 2.73 years. At both time points, severity of tics and the presence and severity of psychiatric comorbidity were assessed. Educational achievements were assessed through structured interviews. Results  Children with TS had a lower passing rate at lower secondary and high school compared to healthy controls. More severe vocal tics were associated with fewer passing lower secondary school at a prospective level. At a cross-sectional level, more severe motor tics were associated with fewer passing high school. Tic severity only influenced children with TS without comorbidity. The severity of comorbidity was found to be associated with the educational level at a longitudinal view, but not cross-sectional. Conclusion  Overall, children with TS had a lower passing rate at lower secondary school and high school compared to healthy controls. We found that this difference was more likely driven by the severity of comorbidities than tic severity. It is important to be aware of academic achievement in children with TS in order to give them the right support and thereby optimize educational opportunities.