Despite the expansion of early intervention approaches for young children with ASD, investigators have struggled to identify measures capable of assessing social communication change in response to these interventions. Addressing recent calls for efficient, sensitive, and reliable social communication measures, the current paper outlines the refinement and validation of the Social Communication Checklist (SCC). We discuss two small studies exploring the psychometric properties of the SCC and the SCC-R (revised Social Communication Checklist), including sensitivity to change, inter-rater reliability, and test-retest reliability, in two samples of children with ASD and one sample of typically-developing children. Results indicate this measure is reliable, sensitive to change after a brief social communication intervention, and strongly related to well-established measures of social communicative functioning.