Content-focused practice-based professional development (PBPD) with active learning is one avenue to support teachers in learning new strategies, practices, and programs. This type of professional development moves away from traditional lectures. In this descriptive study, the authors used a pre-post group design to examine the extent to which a PBPD was effective in teaching participants how to design, implement, and evaluate functional assessment-based interventions. Results indicate participants increased perceived knowledge, confidence, and usefulness and made gains in actual knowledge. The authors conclude with implications, limitations, and suggestions for research and practice.