Children with autism show deficits in social referencing, joint attention, orienting to their names, and social smiling as early as the first year of life. The present study describes the development of the Social Orienting Continuum and Response Scale (SOC-RS), a quantitative scale assessing each of these behaviors during the course of video-recorded Autism Diagnostic Observation Schedule (ADOS) sessions. The SOC-RS was shown to be reliable and valid, and when applied to a longitudinal sample of children studied at 2 and 4 years of age, was shown to be sensitive to decreased levels of social referencing, joint attention, orienting to name, and social smiling in autism. The implications of these findings and potential applications of the SOC-RS are discussed.