Online Parent Training in Early Behavioral Intervention (OPT-In-Early) is a self-directed resource for caregivers of autistic children. Sixty-three parent-child dyads from three states in were randomized to the OPT-In-Early or treatment as usual group. Parents in both groups completed baseline and post-treatment visits, which were targeted for 4 months apart but allowed to go up to 6 months. Compared to parents in the treatment as usual group, parents randomized to OPT-In-Early learned more evidence-based intervention principles from baseline to post-treatment and were rated by observers blind to group and time as increasing their use of these strategies during brief semi-structured interactions with their children. Parent participation in OPT-In-Early did not significantly influence children's social communication as coded from one observation session. Results suggest that parents acquired knowledge and skills in intervention techniques from OPT-In-Early. Longer trials may be needed for gains in child behavior.