A qualitative study of three parents and their toddlers with autism was conducted to investigate the communicative functions underlying parent-toddler interactions and how the instrumental or social nature of one partner's actions influenced the other's engagement. Parent-child interaction videos collected from a separate intervention study were transcribed with thick description, coded for literal and inferential meaning by independent coders, and analyzed for emergent themes following an iterative process of code categorization. Themes converged around the partner as instrument, attempted but missed social connections, and congruent social engagement. A complementary interactional sequential analysis revealed that communicative functions of initiating partners were largely mirrored in their partners' responding actions, suggesting that actively supporting parents to interact with their toddlers socially, rather than prescriptively or instrumentally, may be a potent intervention strategy to address the core social communication challenge in autism during the formative early developmental period. [This paper was published in "Journal of Early Intervention" (EJ1168909).]