This mixed-methods study investigated the English medical vocabulary strategies, needs, and difficulties of Taiwanese medical school students via an open- and closed-ended questionnaire (n = 17), a test measuring vocabulary size (n = 17), student interviews (n = 5), and teacher interviews (n = 3). Students reported using some vocabulary strategies more than others. A statistically significant negative relationship between students’ English vocabulary size and their use of word cards for vocabulary learning was also revealed. Through analysis of the interview data gathered from the medical students and their English teachers, five vocabulary learning difficulties faced by the medical students were uncovered: (1) nonexistent intentional English vocabulary learning, (2) stagnant specialized medical English vocabulary acquisition, (3) lack of sufficient contextualized academic English writing practice with newly encountered specialized medical vocabulary; (4) lack of teacher feedback on the students’ vocabulary use; and (5) lack of pedagogical communication among faculty. The pedagogical implications of these results were discussed with a focus on improving students’ vocabulary learning efficiency in light of their specialized English medical vocabulary needs.