This dissertation explores the impact of special education teacher (SET) turnover on general education teachers (GETs) in K-12 schools. Students with disabilities are increasingly placed in general education settings, where collaboration with SETs is critical. However, high SET turnover rates threaten this partnership. This mixed methods study investigates the relationship between SET and GET turnover and its impact on GET experiences. Findings reveal a positive association, particularly when GETs have more students with disabilities. Additionally, qualitative data suggests SET co-teacher turnover disrupts collaboration and creates challenges for GETs in the following year. To improve outcomes for students with disabilities, the study calls for increased support for teachers and stronger collaboration between special and general education teachers. These findings can inform policies and school-based strategies to improve teacher retention and collaboration, ultimately benefiting students with disabilities. [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.]