In this paper I provide a philosophical analysis of family-based immigration. This type of immigration is of great importance, yet has received relatively little attention from philosophers and others doing normative work on immigration. As family-based immigration poses significant challenges for those seeking a comprehensive normative account of the limits of discretion that states should have in setting their own immigration policies, it is a topic that must be dealt with if we are to have a comprehensive account. In what follows I use the idea of freedom of association to show what is distinctive about family-based immigration and why it ought to have a privileged place in our discussion of the topic. I further show why this style of argument neither allows states to limit nearly all immigration nor requires them to have almost no limits on immigration. I conclude by showing that all states must allow some degree of family-based immigration, and that this is a duty owed not to 'outsiders' seeking to enter, but rather to current citizens.