Self-efficacy is clearly important for learning. Research identifying the most important sources of self-efficacy beliefs, however, has been somewhat limited to date in that different disciplines focus largely on different sources of self-efficacy. Whereas education researchers focus on Bandura's original sources of "enactive mastery," "vicarious experience," "verbal persuasion" and "negative emotional arousal," organizational researchers focus on "learning," "performance prove" and "performance avoid" achievement goal orientations. To date, however, little research has examined the importance of a specific set of self-efficacy sources after fully accounting for the influence of other sources. Data were obtained from 278 adult trainees who completed online Microsoft Excel training. Results suggest that once accounting for achievement goal orientation, Bandura's sources of vicarious experience and negative emotional arousal are still important contributors to pretraining self-efficacy beliefs. As such, organizations seeking to maximize training effectiveness may wish to consider pretraining interventions simultaneously targeting achievement goal orientation, vicarious experience and negative emotional arousal.