Organizational decision making requires the ability to process ambiguous information while dealing with overload and conflicting requirements. Although researchers agree that ambiguity tolerance is a critical skill for making high-quality complex decisions, few have investigated the effects of ambiguity tolerance on self-efficacy to make complex decisions. In the current experiment, 151 participants were randomly assigned to either a moderate complexity or high complexity decision task. Ambiguity tolerance moderated the relationships between task complexity and self-efficacy, and between task complexity and the accuracy of self-efficacy in predicting future performance. In the highly complex task, individuals with a higher tolerance for ambiguity reported higher self-efficacy and more accurate self-efficacy versus individuals with lower tolerance for ambiguity. In the moderately complex task, tolerance for ambiguity had no effects on self-efficacy or accuracy. Implications for research and practice are presented, along with study limitations.