The undergraduate psychology curriculum often does not address guidelines for acceptable participant behavior. This two-part study tested the efficacy of a recently developed online learning module on ethical perceptions, knowledge, and behavior. In the preliminary quasi-experiment, students who viewed the module did not have higher end-of-semester ethical perceptions than a control group, although the experimental group demonstrated increased ethical knowledge and behavior than the control group. Study 2 replicated these findings with a pretest--posttest experimental design at another university. These findings lend support for the module increasing ethical knowledge and behavior, although not necessarily perceptions. However, exploratory analyses suggested that ethical perceptions appear to increase across all research participants through experience.