Significant funds have been allocated in the United States at the federal, state, and local levels to provide teacher professional development aimed at bringing about instructional change and resulting in improved student achievement. One important indicator for quality and effectiveness in professional development is change in teaching practice. This study was designed to observe instructional change among 45 classroom teachers across three data points: at the beginning, in the middle, and at the end of a two-year statewide professional development initiative focused on incorporating formative instructional practices into daily classroom work. Repeated measure analysis results indicated significant changes in providing effective feedback and encouraging student ownership of learning. Change patterns in the classrooms included in this study informed future professional development focus, design, and delivery. Researchers found that implementing a comprehensive teacher professional development initiative to improve instructional quality is promising yet challenging because of differing local implementation plans, organizational structures, priorities, and resources.