This paper studies the reasons for low response rates in online evaluations. Survey data are collected from the students to understand factors that might affect student participation in the course evaluation process. When course evaluations were opened to the student body, an email announcement was sent to all students, and a reminder email was sent a week later. Our study showed that participation rates increased not only when emails were sent, but also when faculty used in-class time to emphasize the importance of completing the evaluations.