Because parents of children with cerebral palsy encounter many challenges, the quality of their parenting varies substantially across time. To understand how and why their parenting behaviors change across time, we examined the contributions of child behavior and parents' psychological needs to explanations of yearly variation in responsive, autonomy-supportive, and psychologically controlling parenting. We also explored whether parents' motivation to take care of their child explained why some parents engage in better-quality parenting than others. Parents (N = 117) of children with cerebral palsy (M[subscript age] = 10.98 years) participated in a three-wave longitudinal study. Multilevel analyses indicated that yearly variations in parents' need satisfaction and frustration related to yearly fluctuations in, respectively, autonomy-supportive and psychologically controlling parenting. Child behaviors had few unique effects on parenting. Parents' autonomous motivation was associated with better overall quality of parenting. We discuss implications for practice and directions for future research.