Integration of general and special education students in the classroom has become common in many educational systems. Researchers have found that some general education teachers may have negative attitudes of inclusion when they are inadequately prepared to instruct in an inclusion setting. The purpose of this causal-comparative study was to investigate the relationship of teachers' professional development (PD) on their attitudes about teaching in an inclusive classroom at a northeast Georgia middle school. Using Vygotsky's sociocultural developmental theory, the research question examined the difference in teachers' attitudes toward inclusion as measured by the Scale of Teachers' Attitudes Toward Inclusive Classrooms (STATIC) based on the number of PD workshops taken. All 150 general and special education teachers at the study site were invited to participate and the sample included 74 teachers who completed the STATIC. Analysis of variance results indicated that teachers who completed 3 or more PD courses had significantly more positive attitudes toward teaching in inclusive classrooms than teachers who took fewer than 3 courses. As an outcome of the study, a PD workshop was created that provided teachers with strategies to operate within an inclusive classroom. Informing administrators about the necessity to expose teachers to PD if they teach inclusion classes is essential to improving teacher attitudes, which creates an environment that promotes student success.