Abstract Recent years have seen intense debate about the causes of the observed decline in the labor share. We extend this inquiry by investigating whether the design and enforcement of competition law and policy are associated with changes in the labor share. Using a panel of 22 industries in 12 OECD economies, we find a positive statistical association between the effectiveness of competition policy and changes in the labor share over the period 1995–2005. This suggests a potential link between the design and effectiveness of competition policy and the labor share, and more broadly to distributional outcomes. Our results reinforce the importance of accounting for country-specific factors, including the design and enforcement of local laws, when examining dynamics in the labor share. The analysis implies that effective competition law and policy could mitigate the decline of the labor share, particularly in settings characterized by low levels of labor protection and limited labor bargaining power. (JEL: E21, E24, E64, J01, J21, K21, L40).