In this article, we discuss the significance of English in the internationalization of higher education and international student mobility, using Kachru's (1985) Three Circles Model of World English. As education is one of the major forms of migration (Liu-Farrer, 2022; Borlongan, 2023) in the so-called 'age of migration' (cf. de Haas, Castles, & Miller, 2020), more and more students are motivated to study abroad to complete their tertiary education. First, we discuss motivating factors both for the internationalization of higher education and international student mobility. Second, we point out how English has been playing a very central role in the internationalization of higher education institutions and international student mobility (Philipson, 2010; Jenkins, 2017) among these factors. Then, we present the dynamics of international student mobility by looking at their global flow, English-medium programs, and English language proficiency requirements. While Inner Circle countries are still the most attractive destinations for most international students, Expanding Circle countries, where English is not an institutionalized medium of instruction in higher education, also value English by expanding English-medium degree programs and requiring English proficiency test scores to admission. Finally, we end the article by reiterating the dominance and utility of English in the internationalization of higher education and international student mobility and its stable position as the language of educational migration.