Whilst the literature on international migration expands at a seeminglyexponential rate, significant statements about the theorisation of migrationare much less common; probably they are hindered by the increasingdiversification of types of migration. This paper first reviews the various typesof migration, and emphasises the need for an interdisciplinary approach to thestudy and theorisation of migration. In the main part of the paper I providea personalised overview of theories of international migration, divided intothe following sections: push-pull theory and the neoclassical approach;migration and development transitions; historical-structural and politicaleconomy models; the role of systems and networks; the ‘new economics’of migration; and finally approaches based on the ‘transnational turn’ inmigration studies. In the conclusion I point up some future challenges totheorising migration: the need to embed the study of migration within globalprocesses of social, economic and political transformation and within thebiographies of migrants’ lifecourses; the importance of also explaining whypeople do not migrate, and the notion of access to mobility as a differentiatingfactor of class and inequality; and the relevance of existential and emotionaldimensions of migration. The paper is explicitly aimed at a student audienceand is intended as a primer to understanding some of the complexities andchallenges of theorising migration.