The framework of a Professional Learning Community (PLC) was adopted and implemented in Guam schools to foster a system of collaborative practice to improve teaching and learning. The problem addressed in this study was how teacher isolation affected the implementation and effectiveness of PLCs. The purpose of this quantitative study was to examine teachers' perceptions of the implementation and effectiveness of PLCs based on seven attributes and the three variables- school level assignment, years of teaching experience, and gender. Data was collected using a one-shot survey. The study population included teacher respondents (N = 125), 63 from elementary and 62 from secondary. Data results determined that results orientation, shared and supportive leadership, and shared mission were always evident in PLC meetings. In contrast, continuous learning, action orientation and experimentation, and collective inquiry were not always apparent. The collaboration attribute was central to the effectiveness of these traits. The study's findings determined that the school-level assignment, years of teaching experience, and gender did not significantly influence the degree of PLC implementation and effectiveness. Even though data findings indicated no significant differences in all three, it was recommended that a holistic and intentional implementation of all seven attributes to effectuate a results-oriented PLC in a collaborative process. Further recommendations for practice include providing training to all school personnel, developing and executing a district-wide PLC implementation plan, and embedding the celebration concept to enable members gain trust, experience the feeling of pride, and achieve a sense of belonging. Recommendations for further research include conducting a pre- and post-survey in a mixed-study approach district-wide to compare the differences of implementation and effectiveness over time. Finally, the study's findings, conclusions, and revelations will help build a community of practice in Guam public schools. [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.]