Improving inclusive middle school science teachers' vocabulary instruction is a critical step toward helping those professionals support the learning needs of all students. In this Institute of Education Sciences (IES)-funded project, inclusive science teachers received professional development using elements of a multimedia-based approach called the Content Acquisition Podcast Professional Development (CAP-PD) intervention process. In this article, the authors discuss the three iterative pilot studies conducted as a part of this project and how each contributed to its development. Drawing on a theoretical framework that considers the characteristics of effective professional development, CAP-PD has three elements: (a) use of instructional videos that highlight the steps of practices and embed modeling videos to demonstrate practice, (b) preproduced instructional materials that support the implementation of evidence-based practices, and (c) feedback for teachers using data outputs from a classroom observation tool developed as a part of this project. Across studies, teachers who engaged in the CAP-PD process made important gains in terms of how much time they spent delivering evidence-based vocabulary instruction and the number of different practices implemented with fidelity. Future research should address questions of the lasting impact of this process on student learning and how to adapt the CAP-PD to help teachers do more than improve their vocabulary instruction.