For over thirty years, research has been conducted on the relative benefits of integrating the sixth through eighth grades within the structure of the K-8 elementary school or of establishing a freestanding middle school structure. While the available research clearly supports the positive effects of the K-8 structure on academic achievement in the middle grades, there has been little study explicitly of students classified as "special needs." This study analyzes the effects of the K-8 versus 6-8 grade configurations on the proficiency rates for sixth and eighth grade special education scores on the 2011 NJ ASK in Math and Language Arts. K-8 and 6-8 configured schools' mean scores were compared in Math and Language Arts to determine if K-8 schools' performance was significantly different than 6-8 schools. Analysis was also conducted for schools that were situated in similar district factor groups so as to account for socioeconomic status. A two-way ANOVA was performed to see if the variables grade configuration and district factor group had an individual and/or a combined interaction effect on special education proficiency rates. To further examine the grade configurations' effect on the dependent variable proficiency rates for special education students, a hierarchical multiple regression was conducted. Within this regression, the independent variable of grade configuration was examined to see if its effects were different after controlling for the variables total school size, mobility rate, economic disadvantage, and percentage of special education students within a school. Finally, the proportion of variance in achievement attributable to the independent and control variables in sixth and eighth grade was compared to determine if there was any difference in their influence on proficiency rates by grade level. The major findings showed that even though K-8 schools outperformed 6-8 schools in Language Arts and Math for special needs students, these results were significant only in the sixth grade. Control and independent variables had more of an effect on sixth grade proficiency rates than in eighth grade, while they also had less of an effect in Math than they did in Language Arts. The results of this study will help district and school-level leaders decide which configuration will be best suited for the special education population in their community. [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.]