A gap exists in education research in the area of district support for campus-based professional learning communities (PLCs). The current study was an examination of practitioner perceptions of district structures and practices that support the development and sustainability of PLCs in public high schools. I examined the perceptions of 341 teachers, campus administrators, and district administrators in a suburban North Texas public school district with three comprehensive high schools. Using a sequential mixed-method design, quantitative data from an electronic survey and qualitative data from face-to-face interviews were collected and analyzed. The findings revealed a generally positive view of central office support among the participants, including consistent ratings from each high school, each campus-level position, each content area, and each level of experience in the district. There was some misalignment of perceptions between campus-level and district-level staff. The study also uncovered a set of best and worst district practices, the six PLC strengtheners and six PLC inhibitors, which were synthesized into a set of recommendations and guidelines for district support for high school PLCs. From participant feedback, I concluded district support is needed and desired by high school practitioners and there are specific district practices and structures that are most effective. While the study results provide a practical set of recommendations for school districts for supporting high school PLC efforts, expanded research is necessary to confirm transferability to school districts of diverse sizes, locations, and demographics.