Migration research developed significantly in the past decades. However, with the life course approach and the concept of transnational migration, there are still two different, as yet largely unconnected conceptual perspectives on migration. Both approaches have their merits but also their shortcomings. This paper tries to overcome these shortcomings by combining the advantages of both perspectives to suggest a unified theoretical concept of transnational life courses (TNLC). TNLC builds on the multidimensional understanding of transnational migration research that (potential) migrants live in multiple social and cultural spaces leading to parallel assimilation and dissimilation processes. This perspective is merged with the life course approach with its chronologically ordered understanding of causality relying on preceding determinants and subsequent outcomes in form of events and periods. Based on data provided by the German Emigration and Remigration Panel Study (GERPS) some simple empirical analyses were conducted to illustrate the potential of the TNLC approach.