Aim: The aim of this study was to describe and identify factors associated with motivation in children with cerebral palsy (CP). Method: Children with CP were recruited for this cross-sectional study. Children were assessed using the Leiter Intelligence Test, the Gross Motor Function Measure, and the Vineland Adaptive Behavior Scale. Parents completed the Dimensions of Mastery Questionnaire (DMQ) and questionnaires on demographics, child behaviour, and family functioning. Results: The parents of 74 children (46 males, 28 females; mean age 9y 2mo, SD 2y 1mo, range 5y 10mo-12y 11mo) completed the DMQ. Just over half of the children (39/74) were classified at Gross Motor Function Classification System (GMFCS) level I, with 13 classified at GMFCS level II, one at level III, six at level IV, and 14 at level V; one child was not classified. The most common diagnoses were spastic hemiplegia and quadriplegia (23 each), followed by diplegia (14). The highest motivation scores were obtained for the dimensions of mastery pleasure and social persistence and the lowest for persistence with motor or cognitive tasks. Age and sex were not predictive of scores on the DMQ. Higher IQ (r = 0.41), better motor ability (r = 0.43), and fewer limitations in self-care, communication, and socialization (r = 0.44-0.53) were positively associated with motivation total score. A negative impact of the child's disability on the family was associated with lower motivation (r = -0.44). Positive social behaviours were positively correlated with motivation (r = 0.38-0.66), whereas hyperactivity and peer problems were negatively associated. Interpretation: High motivation was associated with fewer activity limitations and behavioural problems and reduced family burden. Low motivation may adversely influence a child's functional potential and the effectiveness of interventions. Strategies focusing on the child, peers, adults, or activities are proposed to enhance the children's motivation to engage in more challenging activities