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.