Background: Individuals with intellectual and developmental disabilities (I/DD), including autistic individuals, face challenges in securing and maintaining competitive employment. To fill this gap, the research team developed and conducted a pilot prospective cohort trial of a training curriculum for job coaches, employers, and family members to increase their competency in working with individuals with I/DD. Method: The research team collaborated with 28 community stakeholders to cocreate the DIVERSE (Developing Inclusive Vocational Education and Resources for Success in Employment) curriculum using a community-based participatory research (CBPR) approach. We assessed the preliminary efficacy of DIVERSE by delivering the curriculum to job coaches, family members, and employers and determining the outcome measures before initiation of the curriculum and after completing the curriculum. Participants had up to 6 weeks to complete the curriculum, which consisted of seven modules. This study focused on outcome measures related to the knowledge about I/DD, as well as self-confidence and self-efficacy in working with people with I/DD. Results: A total of 86 participants enrolled in DIVERSE, with 81 of those (94%) completing all modules of the DIVERSE curriculum within 6 weeks. Seventy-eight (91%) (44 job coaches, 22 family members, 12 employers) responded to at least one post-training survey. DIVERSE resulted in an improvement of objective and subjective knowledge about I/DD in quizzes and self-rated questionnaires, respectively. Furthermore, job coaches who completed DIVERSE demonstrated increased self-efficacy and self-confidence in coaching autistic clients and clients with I/DD. They also demonstrated increased self-rated job coaching competencies 3 months after completing DIVERSE. Conclusion: The study signals a promising approach to adapt, develop, and test a training curriculum for job coaches and the I/DD community using CBPR and strength-based approaches. It also demonstrated a preliminary signal for improving knowledge, self-efficacy, and confidence in working with people with I/DD. The DIVERSE curriculum has the potential to enhance the abilities of professionals and caregivers in promoting employment success for individuals with I/DD.