Effective, engaging teacher collaboration contributes to continuous school improvement and overall student success. This formative, internal program evaluation used a combination of objectives-based and improvement-focused models to determine what worked well in mandated PLCs at MHS, what aspects of these PLCs needed improvement, and what suggestions for improvement the participants recommended within an American high school located in Asia. Within this school, collaboration time was mandated as a means of meeting new accreditation performance standards. This program evaluation used a non-experimental, single group, embedded case study design and gathered data via program data, interviews, journal prompts, and program documents to capture the perspectives and experiences of seven teachers participating in a mandated PLC. This evaluation was guided by the following central research question: What are the perspectives and experiences of teachers working within a mandated PLC in an international school? In addition, three focused research questions were used to support this central question: 1. What, if anything, is working well in the mandated PLC? 2. What challenges, if any, have the teachers participating in the mandated PLC faced? 3. What suggestions and recommendations, if any, do the teachers have for improving the quality, relevance, and utility of the PLC? This dissertation's results are informative for school and district leaders. More specifically, they help identify ways to counteract the negative effects associated with mandated PLCs. For instance, teachers recommend more autonomy in selecting PLC groups and the focus of their PLC based on their needs and experiences, as well as the methods they use to collaborate. They also suggest that the district should develop a collaborative culture for educators in addition to providing them with more support in the form of clearer guidance on how to implement the PLC processes and expectations. [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.]