Pre-print, Working paper: In this paper, I study the wage differential between firms' union representatives and their coworkers using a linked employer-employee dataset. On the employee side of the data, the surveyed workers are asked if they are unionized but we do not know which unionized workers are union representatives. On the employer side of the data, I have access to the number of union representatives and unionized workers in each firm. I use this information to construct an indicator of the firm-level probability for a randomly drawn unionized worker to be union representative. This indicator is then used to split the directly observable wage differential between unionized and non-unionized workers into two differentials: one between union representatives and non-unionized workers and another one between unionized workers who are not a union representative and non-unionized workers. Estimates that control for individual characteristics and firm-level fixed effects show that union representatives' wages are 10% lower than those of other unionized workers and non-unionized workers. Additional tests suggest that this gap can be understood as the result of a non-cooperative strategic interaction between employers and union representatives.