Applied Behavior Analysis (ABA) is a systematic approach that utilizes human learning and behavioral principles to assist individuals and groups in achieving their objectives. Despite the increasing diversity of the US population, the ABA field is predominantly represented by White cisgender women. Existing literature stresses the importance of addressing diversity, equity, justice, and inclusion (DEJI) for marginalized individuals, yet most of it remains at a conceptual level. In a recently modified Delphi study, 90% of the suggested DEJI competencies reached consensus among ABA experts, being deemed important for incorporation into preservice behavior analytic training. The study highlights the necessity to raise awareness among preservice behavior analysts about the impact of oppression on marginalized clients and provides explicit training to challenge inequitable systems. The findings underscore the need for DEJI-focused curricula in preservice ABA programs, paving the way for future research and measurement tools in this vital area. [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.]