Purpose: To investigate the relationship between trunk control in sitting and functionality in children with spastic cerebral palsy (CP). Methods: Fifty-eight children with spastic CP were included in the study. Functional abilities were evaluated with the Gross Motor Function Measurement-88 (GMFM-88) and the Pediatric Evaluation of Disability Inventory Functional Skills domain (PEDI-FSD). Trunk control in sitting was tested with the Trunk Control Measurement Scale (TCMS) and the Trunk Impairment Scale (TIS). The scores of the TCMS and TIS were compared with GMFM-88 and PEDI-FSD with Spearman correlation analysis. Results: The total score of GMFM-88 was signi?cantly correlated with the total score of TCMS (r(ho) = 0.90, p < 0.01) and TIS (r(ho) = 0.78, p < 0.01). The total score of PEDI-FSD was also signi?cantly correlated with the total score of TCMS (r(ho) = 0.76, p < 0.01) and TIS (r(ho) = 0.72, p < 0.01). Conclusions: The evaluation of trunk control can provide valuable information for functional abilities of children with spastic CP.