From the Margins to the Center: Supporting Teacher Diversity, Quality, and Retention (M2C) will provide evidence-based professional development (PD) that leads to National Board Certification, an advanced credential for teachers (Absolute Priority 1). The program will directly advance the learning and effectiveness of more than 1,500 teachers, of whom at least 50% will be teachers of color (ToC) and 70% will be teachers serving high-need students. This will support improved learning outcomes for 90,000 students (45,000 each in years 2 and 3) through improved teaching. The program evaluation will provide replicable and scalable learning on solutions to longstanding workforce challenges of quality, retention, and diversity.