During 2012-2016, students with disabilities (SWDs) in Grades 3-5 in an urban elementary school in New York City did not meet the New York State English Language Arts (ELA) standards. The scores had been consistently low for SWDs when compared to their nondisabled peers. SWDs are placed in the inclusion classrooms with an Individual Education Plan that consists of the necessary accommodations that each student requires to access the general education curriculum. The purpose of this case study was to determine if the low ELA test scores for SWDs relate to lack of collaborative practices between coteachers in the inclusion classroom, and to answer the primary research question of how coteachers collaborate to implement students' Individual Educational Plans and devise instructional strategies to accommodate SWDs. Cook and Friend's conceptual framework was used for this study because it directly supports collaboration and coteaching. A purposeful sampling was used to select 4 coteacher pairs (1 special education teacher and 1 general education teacher) from Grades 3-5. Qualitative data were collected from open-ended interviews and lesson plans were analyzed by using provisional and pattern coding. Four major themes emerged from the analysis: coteachers' strategies used when planning lessons for SWDs, classroom accommodation for SWDs, coteachers' instructional strategies, and collaborative relationship in inclusion classroom. The study findings positively influence social change by showing coteachers' need for ongoing professional development that provides effective instructional strategies and collaborative practices for teaching SWDs, with the goal of increasing the percentage of SWDs who meet the ELA state standards. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]