Using the 2007 National Survey of Children's Health, the association between parent-child function and physical activity and television viewing was investigated among a national sample of adolescents in the United States. Parent-child function was measured using the National Survey of Children's Health "Family Function" survey items and confirmatory factor analysis. Multivariable regression described the influence of parent-child function and having a special healthcare need (SHCN) on physical activity and television viewing, and described the differential influence of parent-child function on type of SHCN. Higher parent-child function was associated with more frequent physical activity (relative risk = 1.18, 95% confidence interval: 1.1, 1.3) and less frequent television viewing (relative risk = 0.91, 95% confidence interval: 0.86, 0.96). Controlling for parent-child function, having any SHCN was not associated with physical activity or television viewing. Controlling for type of SHCN, higher parent-child function influenced physical activity for adolescents with autism (p = 0.007) or a functional limitation (p = 0.001). Policy and programmatic efforts to bolster organised parent-child physical activities and reduce caregiver burden might ameliorate disparities in physical activity. (Contains 3 tables.)