Several student and course characteristics were examined in relation to student ratings of instruction. Students at a major Canadian university completed the Universal Student Ratings of Instruction instrument at the end of every course over a three-year period, providing 371,131 student ratings. Analyses of between-group differences indicate that students who attend class often and expect high grades provide high ratings of their instructorsc (p <.001). In addition, lab-type courses receive higher ratings than lectures or tutorials, and courses in the social sciences receive higher ratings than courses in the natural sciences (p <.001). Regression analyses indicated, however, that student and course characteristics explain little variance in student ratings of their instructors (<7%). It is concluded that student ratings are more related to teaching instruction and behavior of the instructor than to these variables.