Abstract: Libertarians support free markets. But most actually existing markets are not entirely free. What, then, should libertarians think markets as they exist in the real world? This paper argues that the correct libertarian position is not an unequivocally “pro-market” one. Not all markets are such as to be deserving of libertarian moral support. And, more surprisingly, not all policy changes in the direction of freer markets are ones of which libertarians ought to approve. Like most political theories, libertarianism’s strength is its compelling vision of an ideally just society. But, again like most political theories, libertarianism faces a serious weakness in providing theoretical and practical guidance about how to think and act in a world that falls well short of that ideal. What libertarians need now, I argue, is a non-ideal theory of markets.