This research seeks to analyze the provisions concerning “mistake” within civil law, emphasizing both theoretical and practical dimensions as articulated in various civil legislations. The investigation is structured into two primary sections: the first addresses the essence of mistake, outlining its general definition and assessing the legal theories that elucidate it. Legal scholars predominantly refer to two principal perspectives—namely, the traditional theory and the modern theory—in their interpretations of mistake. The second one focuses on the examination of mistake provisions in civil law, particularly regarding the types and conditions of mistake. It also considers the regulations pertaining to the proof of mistake and its legal ramifications. The study culminates in several significant findings, the most prominent of which is the recognition of mistake as a mental defect impacting the parties involved in a contract. The traditional theory of mistake, which categorizes mistake into three principal types, is embraced by this study. Additionally, the research presents several recommendations aimed at enhancing the legal application of mistake provisions. These recommendations include broadening the eligibility for individuals to seek contract annulment due to mistake, establishing a defined timeframe for exercising the right to annul a contract, and introducing a legal stipulation that clarifies the materiality of mistake.