This study investigates the effectiveness of implementing clicker-based activities to promote critical thinking in a small-enrollment undergraduate psychology course. Students' performance on knowledge-based tests and critical-thinking assignments were analyzed. Whereas no significant difference was observed in their knowledge-based exam performance, students performed significantly higher on the critical-thinking assignments on the chapters for which they received instruction with clickers. Students' self-reports confirmed that they felt more engaged by using clickers, which aided in developing their critical-thinking abilities. Implications for using clickers in college classrooms as an interactive tool to promote critical thinking are discussed.