Résumé : In the literature, social support is depicted as an important determinant of whether someone completes their doctoral process.However, few studies actually test the impact of social support in sound quantitative designs. The present study provides an incrementalunderstanding of the social support effect by (a) assessing the joint influence of three sources of social support (supervisor, academic peers,and relatives) on the emotions of doctoral students, their perceived progress and intention to persist; and (b) testing the interactions betweenthese three sources of support and the doctoral stage of advancement. To this end, we carried out a longitudinal three-wave study with 446doctoral students from two Belgian universities. The hierarchical regressions showed that (1) only supervisor support significantly predictedthe outcomes of doctoral students and (2) the influence of social support on intention to persist was moderated by the stage of advancementin the doctoral journey. We discuss these results and their implications for further work on social support in light of existing literature ondoctoral persistence.