This qualitative study examined the elements of professional learning communities within Catholic elementary schools. The purpose of this study was to investigate best practices of Professional Learning Communities (PLCs) as reported by elementary principals in a random sample of Catholic elementary schools. The researcher interviewed 14 elementary school principals from various Catholic (arch) dioceses with self-identified successful professional learning communities to understand best practices of PLCs at the building level. The aim of this study was to design a framework for elementary school principals seeking to foster professional learning communities in Catholic schools. Five common themes emerged throughout this study: (a) Catholic mission, (b) collaborative culture, (c) professional learning, (d) relational context, and (e) PLC structure. The findings indicated that the elements found within professional learning community protocols are compatible with the standards of academic excellence in Catholic school education. The major findings indicated that there are five essential strategies for Catholic elementary school principals seeking to foster a sustainable professional learning community process at the building level. The researcher proposed an evidence-based framework for elementary school principals seeking to foster sustainable professional learning communities in Catholic education. This framework, proposed as five essential strategies, was tailored to meet the distinct mission and purpose of Catholic education and contribute to the professional learning community process in Catholic elementary 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.]