With the increasing role of globalization, international market segmentation has become a critical success factor for global companies, which aim for international market expansion. Despite the practice of numerous methods and bases for international market segmentation, international market segmentation is still a complex and an under-researched area. By considering all these issues, underdeveloped and under-researched international market segmentation bases such as social, cultural, psychological, etc. are assessed in this study. In addition, the segmentation methods such as a priori and post methods are discussed in detail based on the extant literature review. As a result, this study is providing an extant inventory of international market segmentation bases and methods grounded on the international marketing literature. Comparisons and assessments of international market segmentation bases and methods in a study will contribute essential understanding and critical insights for global companies.