Students with disabilities have traditionally achieved to a lesser degree than have their nondisabled peers. Since the 1950s the federal government has enacted laws to provide free, appropriate public education to students with disabilities. In the first decade of the 21st; Century the government has produced legislation requiring schools to be responsible for improving instruction for students with disabilities. One of the major trends in accomplishing this task is a move toward inclusive education. This study determined the relationships of assessment type (Standards of Learning (SOL) assessments versus Virginia Grade Level Alternative (VGLA) assessments) and models of service delivery (general education inclusion classes versus special education pullout classes) for students with disabilities in grades 3 through 8 on student achievement in 4 counties in Southwest Virginia. Similar studies have been conducted with varying results noted. The review of the literature includes 18 studies that compared the achievement of students with disabilities who were instructed in the general education classroom with the achievement of students with disabilities who were instructed in the special education classroom. Significant differences were noted in 11 of the reviewed studies. The data were analyzed using chi-square analysis and pairwise comparisons. The findings indicate that there is a relationship between instructional delivery method (inclusion or pullout) and proficiency in reading and math. Students who were educated in the inclusion classrooms tended to have a higher incidence of pass proficient ratings and students in the pullout classrooms tended to have a higher incidence of pass advanced ratings. The findings also indicate that there is a relationship between assessment method (SOL assessment or VGLA) and proficiency in reading and math. Students who were assessed via the SOL assessment tended to have a higher incidence of pass proficient ratings and students who were assessed via the VGLA assessment tended to have a higher incidence of pass advanced ratings. [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.]