The EMI Classroom Assessment Practices questionnaire was developed and administered to 40 EMI (English as a Medium of Instruction) university teachers in Taiwan with the aim of meeting EMI teachers’ needs to conduct learning-oriented classroom assessment. The questionnaire surveyed the teachers in terms of their assessment practices in EMI and their self-perceived skills in these practices. The effects of the medium of instruction (English vs. Chinese) and teacher- and course-related variables related to assessment practices were also examined. The results revealed a high correlation between techniques that were less commonly practiced and those in which the teachers felt less skilled, signaling the possibility that assessment practices in the EMI classroom were dominated by the teachers’ familiarity with techniques rather than by instructional objectives. In addition, the teachers perceived themselves to be less skilled in certain learning-oriented assessment practices, such as self-assessment and designing test items that assess higher-level cognitive abilities. Compared with courses taught in Chinese, EMI courses showed a tendency to involve fewer classroom interactions and to assess students’ higher-order abilities less often, elements which are critical to the emergence of learning. Although the EMI teachers were aware of students’ difficulties with English, these difficulties were not commonly taken into consideration, and accommodations were seldom made. Finally, the teachers’ assessment practices were found to be mediated by variables such as discipline, course size, and the teachers’ focus of assessment. The findings of this investigation have implications for the development and implementation of useful training programs in support of EMI teachers’ professional development in assessment.