The International Baccalaureate (IB), formerly known as the International Baccalaureate Organization (IBO), is an international educational foundation headquartered in Geneva, Switzerland, and founded in 1968. It offers four educational programmes: the IB Diploma Programme and the IB Career-related Programme for students aged 15 to 19, the IB Middle Years Programme for students aged 11 to 16, and the IB Primary Years Programme for children aged 3 to 12. To teach these programmes, schools must be authorized by the International Baccalaureate.
Age range: 11 -16
https://www.ibo.org/programmes/middle-years-programme/
Age range: 16 – 19
https://www.ibo.org/programmes/diploma-programme/