University instructors' classroom assessments play a central role in and inevitably influence their teaching and their students' learning. This paper reports on a comparative interview study conducted in a range of three ESL/EFL university contexts in Canada, Hong Kong and China. Six major aspects of ESL/EFL classroom assessment practices were explored: instructors' assessment planning for the courses they taught, the relative weight given to course work and tests in their instruction, the type of assessment methods (selection vs. supply methods) that they used, the purposes each assessment was used for, the source of each method used, and when they used each method. University instructors were also asked to indicate what they saw as the advantages and disadvantages of the methods they used, and whether they took into account prior student knowledge when making decisions about what assessment methods to use. The findings contribute to a better understanding of ESL/EFL university instructors' classroom assessment practices at the tertiary level in a range of three ESL/EFL university teaching contexts. (Contains 5 tables and 4 notes. Appended are: ESL/EFL Teacher Interview Guide; and ESL/EFL Teacher Interview Sheet.)