Internationalization has been a central concept in university strategic policy for several decades. Internationalization is often a key factor in both university rankings and accreditation processes. Many universities have recruited extensively students and staff globally as well as offering an international dimension within programmes. The upshot is that many university campuses are both multilingual and multicultural. However, policies to promote internationalization may lead to a context where the instructional language is English only. It is instructive to investigate how key actors perceive internationalization and its effects. Do they think it promotes monolingualism or multilingualism? This paper reports on a study into the attitudes of key staff in two faculties at a Dutch university as well as members of the central administration towards internationalization and language use. The results show that while most see internationalization as an unavoidable necessity, they subtly distance themselves from institutional policy and practice, implying a discrepancy between private and public attitudes. The internationalization policy does not stimulate multilingualism, but strengthens monolingualism. The study concludes that the educational system is missing out on the rich heteroglossic and cultural context afforded by internationalization, and suggests that a looser language policy may yield more elaborated learning outcomes.