Résumé : The purpose of the present study was twofold. First, we used the three types of support depicted in Self-Determination Theory (structure, involvement and autonomy support) to examine supervision practices in the doctoral context. Conversely, we used this material to discuss the theory and suggest new developments to it.To this end, we conducted semi-structured interviews with 21 former PhD students (8 completers and 13 non-completers). The data were analyzed using deductive content analysis. The first aim led us to illustrate how supervisors offer structure, involvement, and autonomy support to the doctoral students, and to support the relevance of this theoretical framework in this particular context. The second aim led us to provide three avenues for reflection on SDT.First, a set of practices belongs both to structure and involvement and are therefore at risk of being overlooked in research. Second, there is a thin line between structure and control (and between autonomy support and chaos) and intentions to offer the first may easily turn into providing the second in practice. Finally, we developed the hypothesis that a necessary condition for supervisors to be able to offer positive support to their doctoral students is to consider them as trustworthy.