Purpose <p>Functional Behavior Assessment (FBA) plays a crucial role in reducing challenging behaviors among individuals with Autism Spectrum Disorders (ASD). To date, no empirical studies have investigated the effectiveness of structured FBA training programs on service providers’ fidelity of FBA implementation within the Kingdom of Saudi Arabia (KSA) context. Therefore, this study aimed to evaluate the extent to which a structured, competency-based training program enhances service providers fidelity in implementing both indirect and direct FBA procedures.</p> Methods <p>A multiple-baseline single-case experimental design was utilized across six female service providers employed at an autism center and received a competency-based training based on Behavioral Skills Training (BST). The variables were measured by employing integrity checklists and calculated as the percentage of correctly administered procedural steps. Data were analyzed through Tau-U size calculations and visual analysis.</p> Results <p>During baseline, all participants demonstrated low levels of performance. Following the intervention, all participants showed a substantial improvement in implementing both indirect and direct FBA procedures, achieved and maintained the mastery criterion of at least 90% accuracy. Visual analysis showed strong functional relations between the training and improved fidelity. In addition, the participants’ demographic characteristics, such as educational background and years of experience were interlinked with their rate of skill acquisition.</p> Conclusion <p>A structured, culturally adapted training program based on BST is significantly enhancing the service providers fidelity of FBA implementation for children with autism in KSA. These findings strongly support the role of structured training in creating local capacity for evidence-based practices and high-fidelity.</p>