Three years ago, the Toronto District School Board, the largest in Canada and the fourth-largest in North America, began to explore demonstration classrooms as a way to create a richer model of job-embedded, differentiated, and personalized professional learning. By doing action research and examining a variety of professional learning models from other districts, the school board chose a research-based model that fits the needs of a system serving students from 175 nationalities and speaking more than 80 languages. With the program in its third year of implementation, the Toronto District School Board hosts more than 380 demonstration classrooms representing every grade level, all subject areas, combined grades, half- and full-day kindergarten, single-gendered learning, targeted programming to support closing the achievement gap for English Language Learners, students taking grade 9 applied mathematics, racially marginalized students, and children with special needs. The purpose of demonstration classrooms is to support student achievement by building instructional excellence through the intentional sharing of knowledge and practice. Underlying this vision is a strong belief that all staff and students possess tremendous strengths and attributes. In this article, the authors describe what happens during a demonstration classroom visit and what the Toronto District School Board and educators have learned.