Board-Certified Behavior Analysts (BCBAs) are master's level practitioners who typically provide assessments, write programs, monitor, and oversee implementation of behavior plans, and monitor a learner's progress over time to address skill acquisition and reduce challenging behaviors. BCBAs typically work in ABA clinics, in a learner's home, in the community, or in schools. While actual roles of BCBAs may vary depending on their setting and the population they serve, BCBAs working within a K-12 school setting typically collaborate with other professionals to address behavior related concerns of students and to support teachers who serve students with various needs. According to recent research, BCBAs have the capability to support teachers in a way that may address teacher burnout and high turnover rate and can overall enhance student outcomes. Given the specialized support that BCBAs can provide coupled with the fact that there is little research to examine the scope of BCBAs' roles within this setting, experiences of BCBAs working within a K-12 education setting is worth exploring. Therefore, it was the purpose of this study to explore experiences of BCBAs to better understand how they perceive their roles within a K-12 education setting as well as how aspects of professional collaboration impact their daily practice. Participants described these themes related to their roles: challenging behavior reduction, data-based decision making, consultation and support, and flexibility. Regarding collaboration, the participants described buy-in and pushback, having unclear roles, and mentorship. Their recommendations to enhance their experiences include increasing capacity, specifically with training and resources, working to reduce the negative stigma associated with the field of ABA, revamping the BCBA ethical code to make it more relevant to this setting, initiating a special interest group for BCBAs in the school setting, and ongoing research geared toward effectively merging the fields of education and ABA. [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.]