Purpose: To compare walking activity of children with and without cerebral palsy (CP) between the Netherlands and the United States. Methods: A cross-sectional analysis on walking activity data from an international retrospective comparison study including a convenience sample of 134 walking children aged 7-12 years with spastic CP, classified as Gross Motor Function Classification System (GMFCS) level I (N=64), II (N=49) or III (N=21), and 223 typically developing children (TDC) from the Netherlands and the United States. Walking activity was assessed during a one-week period using a StepWatch™ activity monitor. Outcomes were the daily number of strides, daily time being inactive and spent at low (0-15 strides/min), moderate (16-30 strides/min) and high stride rate (31-60 strides/min). Walking activity was compared between countries using multiple linear regression analyses. Results: Walking activity of TDC was not significantly different between countries. Compared to their American counterparts, Dutch children in GMFCS level I and II showed less walking activity (p<0.05), whereas Dutch children in GMFCS level III showed more walking activity (p<0.05). Conclusion: The absence of differences in walking activity between Dutch and American TDC, and the presence of differences in walking activity between Dutch and American children with CP suggest that between-country differences affect walking activity differently in children with CP.Implications for RehabilitationPhysical activity of children with CP should be promoted in both the United States and the Netherlands.The between-country differences in walking activity illustrate that apart from the severity of the CP walking activity seems to be influenced by environmental aspects.In the promotion of physical activity, practitioners should pay attention to environmental barriers that families may experience for increasing physical activity.