We examined the efficacy of an early autism intervention for use in early childhood intervention (ECI) and mutual gaze as a contributor to social development. Seventy-eight families were randomly assigned to one of three 12-week interventions: Pathways (with a mutual gaze component), communication, or services-as-usual (SAU). The Pathways/SAU comparison concerned the efficacy of Pathways for ECI, and the Pathways/communication comparison, mutual gaze. The Pathways group made significantly more change on social measures, communicative synchrony, and adaptive functioning compared with the SAU group and on social measures compared with the communication group. There were no group differences for communicative acts. The results support Pathways as a potential ECI program and mutual gaze as an active ingredient for social and communication development.