This mixed-methods action research study examined how implementing a Professional Learning Community (PLC) supports the development of metacognitive teaching. Participants were ten technical college science instructors. While PLCs are common in K-12 education, they are less employed at the postsecondary level. There is a gap in the literature regarding PLCs in the context of postsecondary education, and the metacognition of postsecondary level educators. A PLC was used as an intervention over a 15-week semester to aid in the development of metacognitive teaching. Instructor use of metacognition was assessed using pre- and post-surveys, questionnaires, and interviews. The study's results supported literature that suggests that instructors vary in their metacognition, and the PLC fosters metacognitive growth. Data provided evidence that instructors had an awareness of their strengths and weaknesses, but they were not as skilled at changing how they teach. Results of the research study indicated that instructors became more self-aware and improve in the domains of declarative knowledge and procedural knowledge. The PLC might be a place where instructors gain awareness of their strengths, enabling them to compensate for their weaknesses. Additionally, qualitative data suggest that the PLC supports deeply personal and meaningful professional development, transformative learning, and critical self-reflection. Collaboration within the PLC enhances self-regulation by reducing feelings of isolation, validating the experiences of instructors, and motivating them to make instructional changes. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]