Hemiplegic cerebral palsy (CP), the most common subtype, is characterized by high levels of mobility. Despite this, children with hemiplegic CP can face challenges functioning in and adapting to situations of everyday life. The purpose of this cross-sectional study (Hemi-NET database) was to identify factors associated with adaptive behaviour in 59 children with hemiplegic CP (ages 4-18; GMFCS I-IV). Using multivariate regression analyses, the relationship between demographic, medical, and developmental factors and adaptive behaviour (measured by the Adaptive Skills Composite score of the BASC-2) was explored. Results indicate that 34% of children had impaired adaptive skills. An autism diagnosis and lower communication functioning were significantly associated with poorer adaptive skills (R = 0.42, F(4, 43) = 7.87, p < 0.001), while factors such as IQ scores and GMFCS level were not. The results contribute to the growing literature that suggests that clinicians and researchers need to look beyond motor functioning when working with individuals with CP.