In this qualitative study, 11 mothers of toddlers with autism participated in interviews to investigate how they perceived their roles and their competency to support toddlers' social learning in the context of both professional-implemented and parent-mediated early intervention models. The authors conducted a thematic analysis with multiple layers of independent coding. Four resulting themes highlighted challenges and contributors to parent self-efficacy. First, related to child characteristics, challenges were most prominent in the early period as participants adjusted to the diagnosis and reached to connect when social challenges emerged. Second, having a peripheral role in early intervention challenged participants' confidence in their abilities, while receiving guidance to assume an active leadership role supported their sense of efficacy for facilitating toddlers' social learning. In a third theme, participants described specific and general examples of their expertise. Fourth, participants considered the transactional context of parent-child interaction and largely viewed their toddlers' independent wills, natures, and preferences as strengths upon which to build social engagement. The results support the need for early interventionists to promote and leverage family capacity for facilitating toddler learning as social challenges begin to appear for toddlers with autism. [This paper will be published in "Autism: The International Journal of Research and Practice."]