Abstract
Until recently, antitrust laws were rarely enforced in labor markets. Although the existence of labor market power has long been recognized, evidence only recently emerged that such market power regularly arises from sources that are actionable under antitrust law. Since 2010, antitrust agencies have substantially increased labor market enforcement actions. However, many questions relevant to enforcement remain unanswered, such as how to conduct market definition for labor markets and how best to incorporate concentration into models of the labor market. This article reviews how antitrust is beginning to be used in labor markets, the evidence for and against its use, and the remaining evidence gaps standing in the way of more effective use.