Using an epidemiological sample (N = 1,117) and a prospective longitudinal design, this study tested the direct and indirect effects of preverbal and verbal communication (15 months to 3 years) on executive function (EF) at age 4 years. Results indicated that whereas gestures (15 months), as well as language (2 and 3 years), were correlated with later EF (φs ≥ .44), the effect was entirely mediated through later language. In contrast, language had significant direct and indirect effects on later EF. Exploratory analyses indicated that the pattern of results was comparable for low- and not-low-income families. The results were consistent with theoretical accounts of language as a precursor of EF ability, and highlighted gesture as an early indicator of EF.