The present study inquires into associative links between Labor Unionization, Salary Gap and Productivity. It was used an unbalanced dataset of the most capitalized companies for the research to be made. One of the main purpose of trade unions creation is to lower the salary gap within the business entity. As well as provide security and stability for workers. We explained this aspect not only through empirical analysis but also relying on the review of psychological literature about the needs of workers and people in general. Our empirical analysis demonstrates the higher the trade union representation, the lower the salary gap. Such findings may be explained by ‘tournament theory’. As it seems to be suitable to explain the phenomena for steep-hierarchy firms, which constitute the research sample. Finally, the employee productivity seems to be negatively associated with the trade union representation. A further inquiry into this problem seems warranted.