Student achievement in education and inclusive support for students with special needs has been a deliberated topic at the federal, state, and local levels of government. The co-teaching approach aims to provide ways for two teachers to work together to create a more inclusive classroom. The co-teaching approach is also known as co-teaching models and co-teaching strategies. The purpose of this study was to compare the secondary math achievement of students with and without individual education plans (IEPs) in co-teach classrooms to students with and without IEPs in general education classrooms to determine whether there was a significant difference in the State of Texas Assessment of Academic Readiness (STAAR) math achievement of the two groups of students. This quantitative study reviewed the Algebra I end-of-course (EOC) scores of students within a suburban district of 16,000 students with two ninth-grade campuses. The participants in this study consisted of 864 students, with 71 students with IEPs from two ninth-grade campuses. The researcher for the study organized the existing 2022 STAAR Algebra I data collected from the collaborating school district. The student scores in co-teaching and general education (non-co-teach) environments were analyzed using a one-way ANOVA. A two-way ANOVA was chosen to analyze the performance of students with IEPs and without IEPs in both environments. The outcomes of this research exhibit a significant potential for educators, such as teachers and campus administrators. While the data obtained from the study indicates that students without IEPs tend to perform better in a co-teaching context, it is important to note that the presence of both special education and general education teachers in the same classroom is beneficial to all students. The results suggest that co-teaching can be an effective method to support students in both general and special education programs. Therefore, educators may consider implementing co-teaching techniques to enhance the learning experience of their students. [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.]