The role that trade unions play as relevant institutions in the labor market is well known. Unions promote wage increases, reduced working hours, and other improvements in working conditions. In addition, through their actions, they also promote equality, participation, and social protection. Their contribution therefore goes beyond workplace well-being, encompassing a wide range of issues related to economic, individual, social, and democratic well-being. The objective here is to analyze the relationship between trade unions and workplace well-being in the European Union from 2005 to 2020. To achieve this objective, a Generalized Least Squares (GLS) model is employed, through which the effects of union density and coverage on working conditions—described across various dimensions—are estimated. The results indicate that, for most indicators, the variables related to union presence have a positive effect, thereby highlighting the importance of trade unions in promoting workers’ well-being and securing labor rights.