This research brief, published by the Grable Foundation, examines the professional learning opportunities available to teachers, primarily across Western Pennsylvania. It draws attention to professional learning as an essential but often less visible part of the education system, particularly as teachers respond to evolving research, technologies, and student needs. The brief profiles dozens of programs offered by school districts, museums, and other organizations and institutions, documenting the districts involved, teachers reached, and students impacted. Drawing on research and examples from the field, the authors identify sustained, collaborative, peer-led, inquiry-based learning that builds on teachers’ experiences as particularly effective, and report that 95% of teachers successfully implement new practices when supported by peer coaching. For educator preparation faculty, the brief offers examples of how teacher learning can extend beyond initial preparation and how schools and community organizations can support educators’ continued professional growth.