For decades, Research for Better Teaching (RBT) has been studying and learning about high-impact teacher teams, teams that improve student achievement – one meeting at a time. We know that building such teams is not easy. Team time is short; agendas are full. Coaches or teacher leaders don’t often have the time they need to research and plan team meetings. And the demand to meet the needs of diverse learners is pressing every day. But it is possible. And it is vital to our students’ success. When teachers gain collective confidence and skill in how to improve student achievement, they can quadruple the speed of learning, literally obliterating achievement gaps.