This chapter identifies factors influencing doctoral candidates' mobility plans based on empirical studies as well as theories of social inequality and migration. The relative importance of the identified factors is assessed through a series of linear and logistic regressions, which are calculated based on data from a 2010 online survey of doctoral candidates employed at German universities. The theoretical considerations are mostly confirmed: mobility experiences during the previous studies and during the doctorate mobilise doctoral candidates to plan further research periods abroad. Moreover, contextual factors play an important role. For instance, working in an internationalised institutional environment and having regular contact with academics abroad increase the likelihood of developing mobility plans. Regarding social factors, age turns out to be negatively associated with mobility plans. Parenthood also affects mobility plans negatively, but only among female doctoral candidates. Contrary to the hypothesis, we do not find that a high social background significantly increases the likelihood of planning a research period abroad. [For the complete volume, "Academic Mobility. International Perspectives on Higher Education Research. Volume 11," see ED601003.]