The concept of serving students with disabilities in their least restrictive environment is a fundamental principle of the Individuals with Disabilities Education Act. This mandate emphasizes that students with disabilities should receive their education alongside their non-disabled peers to the greatest extent possible. This is often achieved in a co-taught class led by a general education and a special education co-teacher. Frequently, these educators feel unprepared to provide instruction that is adequate to meet the diverse needs of their students. General educators do not feel they have the skills necessary to teach students with disabilities, and special educators question if they possess the content knowledge required to instruct all students effectively. This study explored the perceptions of co-teachers who participated in a yearlong professional development and the implementation of the strategies and protocols of that training. The study also investigated the influence of the distributive leadership theory on establishing parity in the classroom. Ten co-teachers from various areas of the state provided insights into their participation through one-on-one interviews, a questionnaire, and focus group discussions to identify the strengths and weaknesses of the program based on their lived experiences. Data was analyzed through coding and thematic analysis. The results indicated that the participants believed the professional development was instrumental in the success of their partnership and in shaping how they delivered instruction in their co-taught class. Additionally, the study found that the partnership would face challenges in effectiveness without dedicated planning time. Recommendations for future practice stressed the importance of ensuring that the professional development is high-quality, job-embedded, and content-focused and should include coaching and support during and after the training. The importance of administrative support should be recognized and understood as an essential element for successful co-teaching. Future studies should explore different professional development opportunities and investigate the professional development's influence on the students' academic performance in a co-taught class. [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.]