A problem with the construction of an inclusive definition of international education is that the word 'international' has a variety of connotations. It is proposed that the term 'international education' is ambiguous because it appears to refer to contrasting usages in educational studies. International education is frequently discussed in the context of the related field of comparative education, but a different sense of the term has also developed in the context of the theory and practice of education in international schools and other institutions. This paper compares and contrasts the different usages of the term 'international education'. It also discusses internationalism and globalization as contexts for international education, as practised in international schools and other institutions, particularly with reference to the history and programmes of the International Baccalaureate Organization (IBO).