Students with autism spectrum disorder is a growing population in classrooms that require specialized instructional strategies to meet their challenging and unique needs with behavior, academics, and socialization. The purpose of this interpretative phenomenological research study was to understand the lived experiences of general and special educators responsible for providing evidence-based practices in classrooms with a heterogeneous population of students with autism spectrum disorder. Educators are often responsible for teaching students with autism spectrum disorder without given any prior training to prepare them for this task. A qualitative methodological framework guides this study to look at in-depth lived viewpoints of educators who work with students with autism spectrum disorder, and if self-efficacy plays a role in their comfortableness with this student population. Bandura's social cognitive theory is the guiding framework. Ten educators from New Jersey, California, Tennessee, Florida, Texas, and Georgia were interviewed using Zoom to gain insight about their daily experiences, obstacles, trainings, and self-perceptions working within the autism spectrum disorder population of students. Participants were recruited from social media platforms such as Facebook and LinkedIn. Data were coded and then analyzed using NVivo. Results of the study indicate educators feel they need preparatory practices and training to prepare them for the explicit and individualized teaching of students with autism spectrum disorder. Participants stated they were never trained effectively or had to learn to teach students with autism spectrum disorder while on the job. The findings also suggest that when teachers know what they are doing and are comfortable performing duties in the classroom while working with students with autism spectrum disorder, it helps them feel more confident in implementing strategies and interventions to help students with autism spectrum disorder. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]