Aim To investigate how children with cerebral palsy (CP) perform in the Danish school system and which factors are associated with school performance. Method This was a population‐based cohort study including 463 126 children born from 1997 to 2003. Data were extracted from seven national registries. The study encompassed 818 children with CP (483 59.0% males, 335 41.0% females) and 417 731 without CP (214 535 51.4% males, 203 196 48.6% females). We evaluated two primary outcomes: not completing 10 years of elementary school, defined as attending fewer than eight final mandatory exams; and grade point averages (GPAs). Mann–Whitney U tests were used to analyse differences in GPAs and logistic regressions were used to calculate odds ratios (ORs). Results Among children with and without CP, 62.6% and 12.4% did not complete elementary school respectively (OR = 11.85 10.28–13.66). Additionally, children with CP who attended all final exams achieved lower overall GPAs than children without CP (6.6 vs 7.3, p = 0.001). In children with CP, comorbidities, maternal education, severity of motor impairments, and intellectual deficits were associated with increased odds of not completing elementary school. Notably, one‐third of children with CP with apparent normal intelligence did not complete school, despite special educational measures. Interpretation Danish children with CP rarely complete elementary school despite initiatives for a more supportive educational system. The complexity of individual needs in children with CP may be challenging for an inclusive school environment. What this paper adds Children with cerebral palsy (CP) have a high risk of not completing elementary school. Children with CP achieve lower overall grades than children without CP. Motor impairment, comorbidities, and maternal education are associated with poor school performance. Intellectual impairment is the most important predictor of poor school performance. What this paper adds Children with cerebral palsy (CP) have a high risk of not completing elementary school. Children with CP achieve lower overall grades than children without CP. Motor impairment, comorbidities, and maternal education are associated with poor school performance. Intellectual impairment is the most important predictor of poor school performance. This original article is commented on by Lebeer on pages 1273–1274 of this issue.