Mountaineer Mathematics Master Teachers (M3T) is collaborative, teacher-led improvement of mathematics teaching and learning across West Virginia. M3T supports and empowers experienced and exemplary secondary mathematics teachers as math teacher leaders (MTL) to learn and use the tools of improvement science and networked improvement communities (NICs). MTLs recruit and lead Local Improvement Teams (LITs) and Grade-level Improvement Teams (GrITs) of teachers who join together across district lin