The aim of the theoretical/empirical study is the conceptual development of the concept of social disadvantage. Social disadvantage is a technical term as enshrined in the Act no. 561/2004 of legal code, on preschool, primary, secondary, tertiary technical and other training. According to the study authors, the importance of understanding this issue is currently growing. In practice, however, this term is associated with ambiguous interpretations. The study seeks to further develop and expand the findings of a case study of educational schemes of the towns of Krnov and Sokolov, which was focused just on the issue of education of socially disadvantaged pupils. The study describes the legislative basis of social disadvantage and understanding of this concept by pedagogicalpsychological advisory centres and ordinary educators, as was captured by two case studies. In conclusion, based on analytical findings, the authors suggest a division of the concept of social disadvantage in three dimensions and formulate recommendations for practice.