Special education teachers' varying levels of awareness of evidence-based practices (EBPs) leads to personalizing practices that can be either positive or negative for student learning outcomes. There is a gap in practice in the research literature regarding special education teachers' perceptions of why and how they personalize EBPs to teach transition-related skills to students with disabilities. The purpose of this basic qualitative study was to explore special education teachers' perceptions of why and how they personalize EBPs to teach transition-related skills to students with disabilities. Guided by Bandura's concept of self-efficacy, which holds that self-efficacy underlies teachers' perceptions of their ability to conduct effective EBP, the research questions focused on high school special education teachers' perceptions of why and how they personalize EBPs. Purposive sampling was used to choose six high school special education teachers who had taught at least two years to participate in semistructured interviews. Inductive data analysis included open and axial coding and thematic analysis. The findings showed that teachers believed in using the most effective practices available, whether identified as effective through research or their own teaching experiences. Teachers implemented content practices as written but adapted them for content and personalized practices to include transition-related practices to meet students' needs. Participants felt prepared to use content-area EBPs but were less knowledgeable of transition-related EBPs. Teachers wanted additional resources, not further training. This study could lead to positive social change by informing professional development design to increase teacher awareness of secondary transition EBPs and how to personalize them effectively, facilitating successful outcomes for students with disabilities. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]