Teachers should possess adequate knowledge of emotional and behavioral disorders (EBDs) to effectively meet the unique needs of students with EBDs. This study explored the implementation and outcomes of a professional development training program on EBDs. In addition, the study examined outcomes concerning the knowledge of in-service teachers about EBDs and their self-efficacy in working with students with EBDs. This study recruited 81 general education teachers from two Saudi Arabia elementary schools, assigned under the intervention or waitlist control groups. Measures of knowledge and self-efficacy in EBDs were obtained at baseline, immediately after training, and at 5 weeks follow-up. The results demonstrated that teacher knowledge and self-efficacy in working with students with EBDs significantly improved as a result of the training program. In addition, the study observed that teacher efficacy was significantly correlated with their knowledge of EBDs. Improving teacher knowledge and self-efficacy through professional development training will mainly increase their ability and willingness to teach students with EBDs successfully in an inclusive learning environment.