The U.S. education system faces challenges from federal and state mandates, globalization, record numbers of countries outperforming the U.S. on international student exams, and the demand for students to acquire 21st century skills. To meet these challenges, professional learning communities (PLCs) have emerged as an effective practice for teachers to work collaboratively to improve teaching practices, increase student achievement, and enhance school improvement. The purpose of this study was to find the similarities and differences in implementing and sustaining successful PLCs between U.S. schools and Chinese schools as well as the lessons that could be learned from each. This qualitative study, with the tradition of phenomenology, included four participating schools in each country. In each school, one principal and four teachers participated in the study. Data collection included interviews of principals and teachers, classroom observations, and relevant documents; data were coded to allow themes to emerge. The five themes that emerged were (a) strong leadership, (b) collaborative learning culture, (c) efficient structures to support PLC activities, (d) continuous intellectual development for teachers, and (e) challenges and obstacles in functioning PLCs. The implications for teachers, principals, and policy makers provide new perspectives in understanding the phenomenon as a means to educate the 21st century learners and reform outdated institutional philosophies and traditional practices.