To cope with students' problem behaviors, which is a frequently encountered problem within inclusive education implementations, classroom teachers often require some form of in-service training. In considering this issue, the current study aimed to determine the effectiveness of an online problem behavior professional development program (e-ITPDPB) that was explicitly designed for teachers of inclusive education. The study model was the experimental model employing a pretest-posttest control and experimental group design. The study's participants included 60 primary school teachers who were randomly assigned to the experimental (N = 30) and control (N = 30) groups. The obtained study data were analyzed using independent samples t-test and ANOVA. The e-ITPDPB was found to be effective in decreasing the number of problem behavior reports raised by teachers and the diversity of causes attributed to problem behavior and the increase in the employment of positive coping ways by the teachers. Furthermore, the teachers' perceptions of professional competence improved, as did their positive views regarding inclusive education.