Professional sport like most human activities undertaken for pay is subject to Article 23(2) of the Universal Declaration of Human Rights (“Equal Pay for Equal Work”). An athlete’s ‘work’ can be variously construed, however, as entertainment/profit generation, athletic performance, or effort. Feminist arguments for gender wage parity in professional sport based on the former two construals rely on counterfactual assumptions, given that most actual audiences and performances of athletes identifying as female do not (currently) equal those of athletes identifying as (...) male. But both philosophical and scientific accounts of the truth-conditions of counterfactual conditionals of the form ‘If conditions X obtained, then the entertainment value/performance of female athletes would equal that of male athletes’ remain uncertain. Construing athletic ‘work’ as effort, on the other hand, ties remuneration to a quasi-unobservable quantity, with paradoxical outcomes when varying levels of athletic or social disadvantage are taken into account. Appeal to procedural justice, finally, does not yield wage equality unless we make the same counterfactual assumptions, or postulate a right to equal remuneration on unrelated grounds of substantive justice. On either of these approaches, the case for gender wage parity in professional sport requires strengthening. (shrink)