Executive control (EC) is related to mathematics performance in middle childhood. However, little is known regarding how EC and informal numeracy differentially support mathematics skill acquisition in preschoolers. A sample of preschoolers (115 girls, 113 boys), stratified by social risk, completed an EC task battery at 3 years, informal numeracy assessments at 3.75 and 4.5 years, and a broad mathematics assessment during kindergarten. Strong associations were observed between latent EC at age 3 and mathematics achievement in kindergarten, which remained robust after accounting for earlier informal numeracy, socioeconomic status, language and processing speed. Relations between EC and mathematics achievement were stronger in girls than in boys. Findings highlight the unique role of EC in predicting which children may have difficulty transitioning to formal mathematics instruction. (Contains 2 figures and 2 tables.)