The International Baccalaureate (IB) Middle Years Programme (MYP) was first created in 1980. This article charts its historical origins and growth. It offers a critical overview of the operation of the MYP revealing both its geographical distribution disparities and the current picture in terms of external moderation of student work. There are several emerging themes of concern. The exact role of the MYP within the IB "continuum" can be questioned, while the MYP is a complex programme in terms of its philosophy and structure, and remains a little researched and seemingly little understood curriculum.