Background: Encouraging students to adopt a mastery goal orientation can help increase learning and motivation. However, the effect of mastery goal orientation interventions specifically in upper-division online elective psychology courses has not been studied. Objective: The purpose of this replication study was to examine the effects of a mastery goal intervention on fear of failure, mastery and performance-approach goals, self-efficacy, and academic performance over time. Method: Fifty-eight students enrolled in an online upper-division educational psychology course were randomly assigned to an experimental or control group. The experimental group engaged in activities that steered them toward a mastery goal orientation, while the control group completed a stress management activity. Outcomes were measured four times during the study. Results: Contrary to our predictions, there were no significant differences between conditions on any of the outcomes. Conclusion: Although a mastery adoption intervention has been shown to be effective in prior studies, the current intervention had no impact on students in an upper-level online psychology course. Teaching Implications: Considering that a mastery goal orientation is consistently linked to adaptive academic outcomes, potentially impactful ways to apply the intervention are discussed.