Despite the contemporary emphasis on evidence-based practices (EBPs) in autism education, the research-to-practice gap persists. Understanding how newly trained teachers' experiences, knowledge, and beliefs about EBPs influence their instructional decisions is vital to increasing EBP implementation among the next generation of special educators. In this study using a mixed-methods approach, 137 novice special educators in two southeastern U.S. states reported their knowledge, perceptions of social validity, and frequency of use of 12 EBPs for students on the autism spectrum. Follow-up qualitative interviews were conducted with a purposive subsample. Positive behavior supports and visual schedules emerged as the most socially valid and implemented practices. The use of EBPs was primarily driven by teachers' knowledge of the practice and perceptions of its social validity, with teacher preparation experiences shaping both. The results have implications for improving preservice preparation and future implementation of EBPs by attending to teachers' procedural understanding and subjective buy-in.