According to Smith and Nelson [Smith, L.E., Nelson, C.E., 1985. "International intelligibility of English: directions and resources." "World Englishes" 3, 333-342.], "intelligibility" refers to word/utterance recognition, whereas "comprehensibility" is the understanding of word/utterance meaning. This study examines the intelligibility of American English (US English) and Hong Kong-accented English (HK English) to Japanese EFL students, specifically focusing on the relationships between intelligibility and such individual learner differences as perceived comprehensibility of these two English varieties, familiarity with different English varieties, language anxiety, and perceived competence. In terms of both varieties, there was a significant negative correlation between intelligibility and language anxiety, and perceived competence was found as a best predictor of intelligibility. Perceived comprehensibility, on the other hand, significantly correlated with intelligibility of US English only. The extent of familiarity with different English varieties indicated a significant correlation with the intelligibility of HK English but not with the US English intelligibility. Allowing students to be exposed to a wide variety of English appears to be important in an era of teaching EIL (English as an international language). (Contains 4 tables.)