Using data from a large longitudinal sample (N = 1,292) of children and their caregivers in predominantly low-income, nonurban communities, we investigated longitudinal relations between attuned caregiving in infancy, joint attention in toddlerhood, and executive functions in early childhood. The results from path analysis demonstrated that attuned caregiving during infancy predicted more joint attention in toddlerhood, which was in turn associated with better executive function performance in early childhood. Joint attention was a stronger predictor of executive functions for lower-income families. Moreover, joint attention mediated the relation between attuned caregiving and executive functions, and this mediation was amplified for lower-income families. These results highlight joint attention as a key mechanism through which attuned caregiving supports the development of executive functions, particularly for low-income families.