This article examines the internationalization of tourism research in the context of the worldwide growth in tourism and a marked increase in tourism studies. Its goal is to stimulate debate, to encourage further analysis of the directions tourism research is taking, and to foster discussion of the implications of the trends identified. The article is based on a systematic and wide-ranging review of the literature. Five major questions are addressed: what is meant by internationalization; what patterns are emerging; what is driving internationalization; what is the role of language in internationalization; and what is the significance and impact of internationalization? The types and levels of internationalization of tourism research vary considerably but overall levels are rather low. The benefits and disadvantages of internationalization are then discussed in terms of the underlying tension between standardization and diversity. Finally, ways forward are outlined.