Overconfidence occurs if our confidences related to our judgments, inferences, or predictions are too high when compared to the corresponding accuracy. For the current review, I commence with (1) a brief overview of the three most frequently used tasks and measures, then (2) present classroom demonstrations, (3) summarize some major findings, (4) introduce and evaluate models and theoretical accounts, (5) discuss the functional value of overconfidence, (6) briefly mention its relevance in applied settings, and (7) conclude with some final remarks, a summary, and a list of further literature.