The paper aims at clarifying, specifying, and contextualizing the concept of organizational unlearning in the IS literature, through a systematic analysis of the concept. We suggest a definition of unlearning as an intentional practice in order to reduce the possible negative impacts of obsolete knowledge. Reviewing the IS literature based on the suggested definition, we identify four dominant views of unlearning. Using this definition, we empirically explore how organizations apply unlearning in the case of disruptive IT changes. The insight from the empirical study shows a wide range of unlearning practices which are applied to different organizational and technical factors. In addition, we identify six characteristics of the IS context which have direct bearings on applying unlearning practices. Using these empirical insights, we suggest how the concept of unlearning can be clearly defined and specifically operationalized in order to avoid common misunderstanding of this concept. We conclude by commenting on how the dominant views of unlearning in the IS literature can be completed and enriched.