Do people in a rising authoritarian power with pervasive propaganda and information control overestimate their country's reputation, power, and influence in the world? Excessive national overconfidence has both domestic and international consequences, but it has rarely been studied. A survey conducted in 2020 and a pre-registered two-wave survey experiment in 2021 shows that the Chinese public overwhelmingly overestimates China's global reputation and soft power, even during a national crisis. Importantly, informing Chinese citizens of China's actual international image can effectively and significantly correct their factual perceptions of the country's global reputation. It also moderately lowers their evaluations of China and its governing system and their expectations for the country's external success. These effects from simple information interventions are not fleeting, and they indicate that triumphalism and overconfidence can be meaningfully mitigated. The findings are not only of theoretical interest but have significant policy implications.