In this study, we used a randomized control trial (N = 84) to evaluate the effects of a classroom-based motivational interviewing intervention on undergraduate psychology students' test performance. Results indicated that students in the treatment group (n = 38) demonstrated significant increases in their exam grades following the intervention (d = 0.34). However, these changes were not significantly different from students in a control group (n = 43) who received a handout on study tips.