Educators often feel ill-equipped to support autistic students in general education contexts, although research shows that inclusion in these settings can contribute to positive outcomes. Professional development (PD) in evidence-based practices (EBPs) for autistic students can address this need; however, it is essential to understand the mechanisms by which PD can improve educators’ EBP use. Through an explanatory sequential mixed-methods design (QUAN→ QUAL), the authors gathered quantitative (Phase 1) and qualitative (Phase 2) data from 86 educators (special educators, general educators, and paraeducators) serving autistic students in general education elementary school classrooms. Using survey data on educators’ reported EBP training and use, the authors evaluated the effects of different training types (conference, in-service workshop, pre-service preparation, webinar, coaching/consultation) on educators’ use of EBPs for autistic students. The authors explored educators’ training experiences that facilitated their EBP use. The authors applied an established professional development framework to qualitative interview data to identify how key PD features (active learning, collective participation, content focus, cohesion, and sustained duration) have been accessed by educators and how they describe these as enabling their EBP use. Results demonstrate that pre-service training, in-service district or school-provided workshops, and coaching or consultation predicted EBP implementation. In addition, educators highlighted key PD features that facilitated EBP use, such as active learning. The authors discuss implications and guidance for incorporating these features within existing PD models to enhance EBP use for autistic students.