Students in rural schools have the potential to achieve at high levels; however, they need support to develop this potential. Research indicates a particular need in the area of STEM education. This study looks at how to enhance school-wide instruction, collaboration, and assessment related to increased student participation in coding and computer science. Using data from the first of a 5-year project funded by the U.S., Department of Education, we look at the effects of participation in professional learning on rural schoolteachers' self-efficacy for teaching computer science and coding, and their experience implementing coding into classrooms. Results indicate participation in systemically supported professional learning increased teachers' self-efficacy for teaching computer science and the emergence of a whole-school computer science culture.