This study examined the independent and mediated associations between maternal depression symptoms (MDS), mother-child interaction, and child executive function (EF) in a prospective longitudinal sample of 1,037 children (50% boys) from predominantly low-income and rural communities. When children were 6, 15 and 24 months of age, mothers reported their level of depressive symptomatology. At 24 and 36 months of age, mother-child interactions during play were rated for warmth-sensitivity and harsh-intrusiveness, and dyadic joint attention and maternal language complexity were assessed from a book sharing activity. Children's EF (i.e., inhibitory control, working memory, and set shifting) were assessed at ages 36 and 48 months using a battery of six tasks. Results indicated that MDS at ages 15 and 24 months were negatively associated with children's EF at age 48 months. Additionally, harsh-intrusive mother-child interactions partially mediated this link. Although warmth-sensitivity, dyadic joint attention and maternal language complexity were all longitudinally related to EF, they did not serve as mediating mechanisms between MDS and EF. These results were obtained while controlling for multiple demographic factors, children's earlier cognitive abilities, maternal general distress and childcare experiences. Findings from this study identify 1 mechanism through which early exposure to MDS could be related to children's EF.