This study examined the direct and indirect pathways from maternal effortful control to 2 aspects of children's self-regulation-executive functioning and behavioral regulation-via maternal emotional support. Two hundred seventy-eight children and their primary caregivers (96% mothers) participated in laboratory visits when children were 4 and 5 years, and teachers reported on children's behavior at kindergarten. At the 4-year assessment, maternal effortful control was measured using the Adult Temperament Questionnaire (Evans & Rothbart, 2007) and maternal emotional support was observed during a semistructured mother-child problem-solving task. At the 5-year assessment, children's executive functioning was measured using laboratory tasks designed to assess updating/working memory, inhibitory control, and cognitive flexibility, whereas behavioral regulation was assessed via teacher-report questionnaires on children's attention control, discipline and persistence, and work habits. Results from structural equation modeling indicated that, after controlling for child gender and minority status, and maternal education, maternal effortful control was indirectly associated with both child executive functioning and behavioral regulation through maternal emotional support. Maternal effortful control had a direct association with children's teacher-reported behavioral regulation but not observed executive functioning. These findings suggest that maternal effortful control may be a key contributing factor to the development of children's self-regulatory competencies through its impact on maternal emotional support.