According to the hybrid model (van Bergen, van der Leij, & de Jong, 2014), the significant association among executive functioning (EF), reading, and math may be partially explained by parent-reported EF's role as a common risk and/or protective factor in reading and math (dis)abilities. The current study used a sample of 434 twin pairs (M[subscript age] = 12.12) from Florida to conduct genetically sensitive modeling on children's parent-reported EF, reading, and math skills to determine the common and unique etiological influences among the three domains. EF was measured through parent report and reading and math were measured with standardized test scores drawn from Florida's Progress Monitoring and Reporting Network as well as standardized parent-administered assessments collected by mail. Our trivariate Cholesky modeling showed that no matter which parent-reported EF component was modeled, the overlap of parent-reported EF with reading and math was explained by common genetic influences. Supplemental analysis suggested that this might in part be due to general parent report of problem behaviors. Additionally, significant environmental influences, with higher shared environmental overlap than previous work, were also found for reading and math. Findings indicate that poor parent-reported EF is a common cognitive risk factor for reading and math disabilities, which is driven by a shared genetic basis among all three domains.