We present, discuss and compare four different theoretical approaches to the idea of a labor market, with a focus on how sociological approaches differ from mainstream economic treatment of labor markets and their issues. Topics discussed include labor market segmentation, unequal power relations, normative and network-dynamics, institutionalisation of labor market constraints, regulation, and the relation between social class and labor markets. Approaches and concepts are illustrated using own (applied policy-)research and recent public debates on labor market policy and (de)regulation.