This paper argues that mobility and migration have always been an intrinsic part of human development. Migration can be considered as a fundamental capabilities-enhancing freedom itself. However, any meaningful understanding of migration needs to simultaneously analyse agency and structure. Rather than applying dichotomous classifications such as between forced and voluntary migration, it is more appropriate to conceive of a continuum running from low to high constraints under which migration occurs, in which all migrants deal with structural constraints, although to highly varying degrees. Besides being an integral part of human development, mobility also tends to affect the same structural processes of which it is part. Simplistic positive-versus-negative debates on migration and development can be overcome by integrating agency-structure dialectics in the analysis of migration impacts. This paper argues that (i) the degree to which migrants are able to affect structural change is real but limited; (ii) the nature of change in sending and receiving is not pre-determined; and (iii) that in order to enable a more focused and rigorous debate, there is a need to better distinguish and specify different levels and dimensions at which the reciprocal relationship between human mobility and development can be analysed. A critical reading of the empirical literature leads to the conclusion that it would be naïve to think that despite their often considerable benefits for individuals and communities, migration and remittances alone can remove more structural development constraints. Despite their development potential, migrants and remittances can neither be blamed for a lack of development nor be expected to trigger take-off development in generally unattractive investment environments. By increasing selectivity and suffering among migrants, current immigration restrictions have a negative impact on migrants' wellbeing as well as the poverty and inequality reducing potential of migration.