Abstract: The paper provides a theory of freedom of speech based on the new institutional political economy. Through politics individuals seek to achieve collectively what they would not be able to achieve individually, forming institutions of social control. But institutions have costs which need to be discovered. Freedom of speech facilitates information discovery about the subjective costs of social institutions. Those costs are not only discovered but created through the acts of speech and expression. The paper develops this institutional approach by contrasting and complimenting against the three dominant theories of free speech: Mill’s marketplace of ideas theory, Meiklejohn’s democracy theory, and Baker’s liberty theory. The paper then shows how the institutional theory can be meaningfully applied to two common questions in freedom of speech debates: that of protest on publicly accessible property, and the relationship between freedom of speech and political correctness.