Sociological theories of migration and refugee movements are reviewed and revised in the light of recent developments in structuration theory. Specifically, the dichotomy between ‘voluntary’ and ‘involuntary’ or forced migration is replaced by a continuum between proactive and reactive migration. A systems model is proposed which identifies predisposing factors, structural constraints, precipitating events, enabling circumstances and system feedback. A multivariate typology of reactive migration is described and some policy conclusions drawn.