This resource presents and describes a model for teaching and learning mathematics responsively in the elementary and middle grades. Developed through the Responsive Math Teaching (RMT) project -- a seven-year collaboration between teachers, teacher leaders, school and district administrators, and researchers from a network of K-8 urban schools -- this book equips any math educator with the tools to enhance instruction and increase equitable outcomes for students and communities historically underrepresented in mathematics. Chapters pair research-based instructional practices with real examples to show how this model has been successfully implemented in actual schools, often under challenging conditions. Each chapter includes classroom vignettes and then breaks down the topic into jobs or responsibilities for teachers, indicating their specific role in supporting their students. The authors provide tools to assist teachers in the decision-making needed to carry out these responsibilities in the classroom. Topics include the components of a responsive mathematics lesson, comprehensive lesson planning guidance, building a responsive classroom community, and supporting responsive teaching as an instructional leader. Whether you are a classroom teacher, teacher educator, or leader, this book can guide you in understanding and reframing your responsibilities, challenge existing norms around mathematics, empower your students as problem-solvers, and ultimately cultivate joy in mathematics teaching and learning.