Wage discrimination among professional sports has long stood as a concern not only to labor/sports economists but also to practitioners, since payment stays influential to both organizational performance and employee productivity. If wage discrimination permeates through professional sports teams, working incentives and teamsmanship will even be negatively affected. This study turns back to previous studies with scoping review method to analyze the issue of wage discrimination among professional sports. We find that academia recently takes ethnicity and nationality as the critical element of wage discrimination, as well we further discuss the causes of wage discrimination. Becker's market discrimination theory, winner's curse, and regulations are applied to understand wage discrimination. Finally, our academic and practical arguments are also given as references to future researchers and professional sports team managers.