Only one in three adults in the United States meets the weekly recommendation for physical activity (PA). The presence of children in the home may restrict adult PA. The purpose of this study was to examine the association between adult moderate and vigorous sport, fitness, and recreational physical activities and the number and age (0–5 and 6–17) of children in their household. Secondary data were drawn from the National Health and Nutrition Examination Survey (NHANES) from 2007–2016. Adults with complete survey data for self-reported moderate (MPA) and vigorous physical activities (VPA), number of children in the home, and other sociodemographic variables were included. The final sample included 2034 adults from 22–65 years of age. Analyses included ANOVAs and separate multivariable regression analyses to determine if the number of children in the household aged 0–5 and 6–17 were significant predictors of weekly moderate-to-vigorous physical activity (MVPA) after controlling for covariates. For MPA, no differences were found between adult PA regardless of the number and age of children in the home. For VPA, adults with two or more children aged 0–5 reported 80 fewer minutes of weekly VPA (p< 0.05) compared to those with no children or just one child in this age group after controlling for all covariates. Finally, adults with three or more children in the household aged 6–17 reported fifty fewer minutes of weekly VPA (p< 0.05) compared to those with no children, one, or just two in the household. These findings highlight a need to support the vigorous PA behaviors of this population, as the majority of the family-based PA intervention studies to date have primarily focused on family dyads.