CAPACiTY: Preparing Teachers (CAPACiTY-PT), submitted to the National Science Foundation’s Computer Science for All program under the High School Strand (Medium RPP Size class), is a collaborative Research Practice Partnership (RPP) between the Georgia Institute of Technology and Georgia computer science (CS) educators in rural and rural-fringe school systems. The RPP seeks to address an urgent problem of practice - critical gaps in CS pedagogy and content knowledge among Georgia’s CS teachers. Building on the work of our NSF STEM+C project, Culturally Authentic Practice to Advance Computational Thinking in Youth (CAPACiTY), the RPP aims to achieve four major goals: 1) To determine, through a needs assessment, the range of skills necessary for teachers to effectively implement CAPACiTY high school CS courses, 2) To design, build, and implement a 120-hour, 14-month-long online professional learning (PL) experience that will provide CS teachers with the requisite knowledge and skills to successfully implement CAPACiTY, 3) To assess the effect of the CAPACiTY PL program on teachers’ understanding of disciplinary and pedagogical content knowledge, and their ability to teach CS skills and promote student engagement using the CAPACiTY framework, 4) To assess the transferability of CAPACiTY by examining variations in curriculum implementation and contextual factors influencing implementation in different school settings.