Segmentation of labour markets has been attracting researchers' interest from the 19th century to the present day. The article aims to reveal the essence of labour market segmentation and its main characteristics, to review development of labour market segmentation theory and to highlight the modern approach to labour market segmentation. The main priority of segmentation theory is that labour market is split into certain segments which are being formed by economic, political and social forces; it also points out segmentation reasons and differences in characteristics of individual labour market participants. Labour segmentation models define employees as labour groups or market segments. Research methods used are based on systemic and logical analysis of works done by both Lithuanian and foreign researcher