Model overconfidence is a phenomenon in artificial intelligence where a model exhibits an excessively high degree of certainty in its predictions or generated answers, even when those outputs are inaccurate or incorrect. This condition arises when an algorithm fails to properly calibrate its uncertainty, leading to a disparity between its perceived or stated confidence and its true empirical accuracy. It can manifest numerically through inflated predictive probabilities or linguistically through assertive phrasing in natural language outputs. Consequently, model overconfidence poses substantial risks in real-world applications by obscuring errors, conveying a false sense of reliability, and leading users to place unwarranted trust in flawed information.