In this chapter we discuss the various approaches to the study of literacy and illiteracy in Japan. Research on this topic falls into disciplines such as educational, historical, and linguistic studies. A common feature of historical approach is to attempt to determine the ratio of literacy. The difficulty in this field is that the bases on which individuals are classified into the side of literate or the side of illiteracy is arbitrary. Literacy in the context of educational approaches based on the competencies concept by the OECD gradually came to promote “literacy for work”. This trend, however, is in decline due to the excessive emphasis on the standard variety of literacy. Participant observation is a current feature in linguistic approaches. Such an ethnographic approach shows illiterate people possess a “vernacular literacy” which differs from the “standard literacy” and includes specific strategies to overcome the literacy problems linked with their daily lives by paying attention to specific local situations and literacy in use. Focusing on the exclusive function has been one notable trend in Japanese sociolinguistics. Single and dominant “Literacy” (with capital L) easily monopolizes the construction of social knowledge and that is how illiterate people such as people with disabilities are socially rejected. Another notable recent trend is in adopting a disability studies view on literacy and to applying its social model to literacy studies. A social model on literacy enables us to recognize new understanding, which is that literacy and illiteracy should not be seen as a personal responsibility, but as a socially created problem.