The number of international students in Japan has continued to increase at a rapid pace and has featured very prominently in the so-called internationalization of higher education. International students had been expected to become a catalyst for internationalization and university reform. Recently, however, concern has been raised about the reported decline in the "quality" of international students. This article uses a case study approach to examine the student-quality issue and conducts a review of the closely related problematic educational environment for international students at Japanese universities. Whereas educational-quality problems tend to affect all students, they invariably affect international students to a greater extent because of language obstacles and a lack of awareness regarding cultural and educational differences. The article concludes that for Japanese universities to effectively sustain the current number of international students, particular attention must be given to the improvement of classroom instruction and other educational support. (Contains 1 note and 3 tables.)