Students with disabilities in Grades 3-5 in a Georgia school are not meeting state academic standards. The No Child Left Behind Act requires schools to ensure that all students meet these standards; those schools that do not make gains enter into School Improvement status. This study was conducted to determine if staff development that focused on inclusion had a positive impact on student achievement and teacher self-efficacy as measured by the Criterion Reference Competency Test (CRCT) and Teachers' Sense of Efficacy Scale (TSES). Bandura's social cognitive theory served as the theoretical foundation. A quantitative, cross-sectional survey design measured the difference between mean CRCT scores of 2 cohorts of students with disabilities in Grades 3-5 (n = 550); mean TSES scores of 2 cohorts of teachers of these students (n = 25) were also assessed. Cohort 1 consisted of students taught by teachers prior to the implementation of a 12-week inclusion program; cohort 2 consisted of students taught by teachers after the implementation of an inclusion program. An independent "z" test was conducted to test the null hypotheses that there was no significant impact of inclusion on student achievement. An independent "t" test was conducted to test the null hypothesis that there was no significant impact of inclusion on teacher self-efficacy. The "z" and "t" tests failed to reject the null hypotheses, suggesting inclusion teacher training did not result in higher student achievement scores or higher teacher self-efficacy. Future research on the impact of inclusion staff development should include increasing training time to a full school year. Implications for social change include a better understanding of an inclusionary staff development program and teacher efficacy, which could lead to an increase in student achievement. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]