Some scholars have treated overconfidence as an individual difference—that is, assuming the tendency to be overconfident is stable within a person and differs meaningfully from person to person. We question this assumption. In two papers, we investigate consistency within individuals between the three forms of overconfidence—overestimation, overplacement, and overprecision—in multiple domains, at multiple times, and with multiple measures. We find mixed evidence of trait-like consistency. We do find some evidence of within-individual stability across domains and time points. However, we find little consistency across different measures of the same form of overconfidence—specifically overprecision. Instead, we find more consistent evidence that overconfidence varies situationally and contextually.