Recent studies have shown that the number of teachers in Germany is decreasing dramatically. In contrast, the rate of student teachers discontinuing their studies is rather high, and further increases the shortage of teachers. To address this issue, we investigated student teachers' social support networks by using a social network approach. Guided by the social cognitive career theory, the mediating role of barriers (i.e. perceived disapproval of influential others towards the chosen career path) on the relationship between supports (i.e. social support quality) and students' dropout intention was analysed. Data were collected from 165 German student teachers at the beginning of their studies and six months later. In summary, this study has identified students' perception of influential others' disapproval towards their chosen career path as a boundary condition for the indirect effect of social support on their dropout intention.