Purpose To identify determinants of spoken language comprehension (SLC) in children with cerebral palsy (CP). Materials and methods Cross-sectional data of 207 children with CP were included: 82 toddlers (18 months–3;11 years), 59 preschool children (4;0–5;11 years), and 66 schoolchildren (6;0–8;11 years), across all Gross Motor Function Classification System (GMFCS) levels. SLC was assessed using the Computer-Based instrument for Low motor Language Testing (C-BiLLT). Potential determinants were retrieved from medical files and through parental questionnaires. Per developmental stage, multivariable regression analyses were used to assess determinants of SLC. Results Fifty-nine percent of the children showed below average SLC. Significant determinants for SLC differed per developmental stage. In toddlers: age, motor type, functional communication and speech function (R 2 = 0.637); in preschool children: functional communication, speech function and language activities (R 2 = 0.820), and in schoolchildren: functional communication, intellectual functioning and arm-hand functioning (R 2 = 0.807). For all developmental stages, functional mobility was not a significant determinant. Conclusions A large proportion of children with CP across all GMFCS levels have SLC impairments. Findings indicate that SLC is strongly determined by functional communication classified with CFCS. We recommend standardized assessment and monitoring of SLC in all children with CP. IMPLICATIONS FOR REHABILITATION Children across all GMFCS levels can experience difficulties in spoken language comprehension. At all developmental stages, functional communication (classified with CFCS) is an important determinant of spoken language comprehension. Standardized assessment and monitoring of spoken language comprehension, language production, speech, and communication of all children with CP, is strongly recommended. When children show below average performances, especially in spoken language comprehension, intervening with speech and language therapy and guidance for parents, is advised.