This paper used a nationally representative sample of children from the United States to examine the extent to which physical activity and sports participation may promote growth in children's executive functions (EFs), attention, and social self-control over time. Using data from the ECLS-K:2011 (N = 18,174), findings indicated that regular physical activity predicted growth in EFs and attention from 3rd to 4th grade ([beta]s = 0.03-0.05) but not from kindergarten to 1st grade. After controlling for the frequency of physical activity, participation in group sports predicted increases in EFs, attention, and social self-control during both periods ([beta]s = 0.02-0.04). Though modest in size, the findings suggest that encouraging children to engage in more frequent and more team-based activity will benefit the development of their EFs and related skills, and especially so for children in middle childhood.