As an expanding field of interest, the individual differences approach emphasizes the importance of focusing on variations among individuals to examine cognitive processes in greater detail. Studies in this context demonstrate that eye movements are a significant performance outcome contributing to the investigation of individual differences. This review focuses on the role of eye-tracking methodology in uncovering individual differences observed in reading behavior. For this purpose, information is first provided about the eye-tracking method, its components, and general findings on eye movements in reading studies. Subsequently, studies examining the relationship between eye movements measured during reading and individual differences such as reading ability, language experience, working memory capacity, age, and gender are summarized. In general, it is observed that there are notable individual differences in reading behavior, and eye-tracking is understood to be an effective method for uncovering these differences. Finally, potential issues related to the eye-tracking method are discussed, alternative solutions are proposed, and the necessity of eye-tracking methodology is emphasized for its practical contributions to identifying individual differences in reading behavior.