Modeling as a scientific practice in K鈥?2 classrooms has received a wealth of attention in the U.S. and abroad due to the advent of revised national science education standards. The study described herein investigated how a group of high school chemistry teachers developed their understanding of the nature and function of models in the precollege classroom through participation in a yearlong professional development program designed using model-based inquiry (MBI) as a framework. Further, we sought to understand the factors that catalyzed or hindered the incorporation of this pedagogy into the participants鈥?classrooms. It was found that the program positively influenced the teachers鈥?understanding of modeling as a scientific practice and facilitated growth in navigating pedagogical and conceptual challenges towards implementing modeling practices in their classrooms.