This essay examines the arguments that many self-proclaimed libertarians make against unionization. It examines whether unions could be expected to arise in a libertarian utopia; whether we could expect them to arise in both the private and the public sector; what limits, if any, we could expect to be imposed on union organizing and behavior; and specifically, whether rules that make the workplace a union shop – that is, a place where all non-management employees are required to be members of the union and contribute to the cost of collective bargaining, or whether rules similar to those embodied in what are typically called “right-to-work” laws are more likely to prevail and be thought consistent with the demands of libertarianism. Finally, I close by examining the relationship between libertarianism and some popular conceptions of liberty a little more closely and argue that, while many people who think of themselves as libertarians believe that maximizing individual negative liberty is fundamental, this is actually a mistake. Libertarianism actually rejects that concept of liberty in favor, I will argue, of a more republican conception, under which liberty is defined as an absence of domination, and a high degree of unionization and this form of liberty are totally compatible.