This paper focuses on the links between migration and sustainable livelihoods, looking in particular at the institutional factors that connect the two. It argues that much of the development literature makes the false assumption that sedentary patterns in society are the norm, instead making the case that migration is often the rule, rather than the exception. It concludes that migration should be seen as just one of the livelihood strategies open to households, that it is often combined with other strategies, and that it is frequently a two-way process in which migrants maintain close links with their areas of origin over a much longer period than is frequently assumed. Pointing out the range of different types of migration, ranging from voluntary to forced, the paper highlights the complex institutional factors involved in determining who is able to migrate, and who benefits most from it.