This paper investigates the relationship between distributive injustice and political obligations within the confines of the fair-play theory of political obligation. The fair-play theory regards society as a scheme of cooperation for mutual benefit. Its key normative claim is that it is wrong, because unfair, to draw the benefits of cooperation without shouldering a fair share of the burdens. The fair-play theory takes this principle to explain why we are under a political obligation to follow state directives. A question that has been overlooked in the literature is how this theory is supposed to apply in societies that do not distributive benefits and burdens fairly. Do the disadvantaged really have a duty to 'play fair' when they are not in possession of a fair share of things like economic opportunities and protection? In this paper, I discuss the relationship between fair-play obligations and substantive distributions of benefits and burdens. I suggest that the most plausible approach is to take a proportionality-based approach according to which the disadvantaged are expected to reciprocate less than the advantaged. This answer, however, runs into trouble because it seems incompatible with the non-gradual nature of legal obedience. I canvass the responses available to the fair-lay theory to get out of this trouble, and suggest that the most promising consists in widening the scope of the theory.