Professional development is best when embedded in one's practice and linked directly to the classroom. Opportunities for teachers to identify specific areas of concern in their classroom and problem solve solutions via action research promotes a culture of inquiry. This culture of inquiry is enhanced when teams of teachers collaborate and share their action research experiences. In this study, action research training was provided to teachers to create a trained cohort of action research teachers within the school. Members of this cohort voluntarily joined with other teachers interested in classroom action research and participated in a professional learning community (PLC). The members of this PLC initiated classroom action research projects and met collaboratively as a PLC. The study examined what collaborative practitioner inquiry contributed to teacher professional development and how my leadership contributed to teacher professional development. Data were collected through the administration of a survey, interviews, transcriptions of PLC meetings, and my research journal. Findings indicate that participants benefited from the provided professional development and my leadership as a result of the intervention. Teachers applied the professional literature and used data to inform their instruction. Teacher collaboration was enhanced and teachers examined instructional practices. Lastly, my leadership enhanced teacher application of action research. [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.]