Professional development is necessary to support and empower teachers in meeting the high stakes demands of mathematics teaching and to ensure equitable, accessible, and high-quality instruction for all students. Using the Interconnected Model of Professional Growth, we designed and implemented a longitudinal, multi-faceted professional development project for teams of elementary general education and special education educators to enhance instruction in their inclusive elementary mathematics classrooms. Focused on high-quality mathematics tasks and co-teaching models, we explored changes in both instructional and collaborative practices. Findings indicated statistically significant increases in educators' mathematics content knowledge and pedagogical content knowledge. Additionally, statistically significant improvements in observed teacher facilitation, student engagement, and co-teaching practices were found. Implications for practice and research are discussed.