Creativity, Action, Service (CAS) forms a core component of the International Baccalaureate Diploma Programme. CAS frequently includes intergenerational practice involving school students and older adults. This article reports the development of a typology to describe and analyse learning that arises from intergenerational practice in three dimensions comprising the type of intergenerational relationship forming the context for learning, what is learned as an outcome of the intergenerational interaction, and how learning is accomplished. It also reports the validation of the typology in a pilot study examining the extent of intergenerational practice in the context of CAS in UK schools offering the IB Diploma, with an aim to internationalize this research in the future. (Contains 1 figure.)