There are few validated remote tools that can be used to assess for autism and to capture subtle changes in children’s social communication over time. Recently, user-centered design principles were applied to develop a parent-mediated remote assessment, the Reciprocal Imitation and Social Engagement Child Play Protocol (RISE CPP) to enable researchers to capture micro-level behaviors in children, while promoting useability for researchers and families, reducing caregiver burden, and maintaining reliability. This paper describes a pilot study to validate the RISE CPP as a tool to support clinician diagnosis of autism. Thirty-eight caregiver-child dyads (24–41 months, M = 34, SD = 4; 86% male) completed a remote parent-mediated assessment at home (RISE CPP) and an in-lab clinician-led assessment (Autism Diagnostic Observation Schedule; ADOS-2). Independent clinician diagnosis based on observations across the remote and in-lab assessments showed agreement for all but one child (K = .89). Clinicians completing in-person and remote assessments reported similar levels of confidence in their diagnoses, t(37) = 0.93, p = .36, d = .15. Mixed-methods analysis revealed unique benefits and challenges to the remote and in-person assessments and suggested that both assessments were acceptable to caregivers. Results provide preliminary support for the RISE CPP as a diagnostic tool. The remote administration may increase equity for clinical and research diagnostic assessments among families who are traditionally underserved and underrepresented in research.