Scholars have demonstrated that one of the most important factors that graduate students use to ascertain the quality of their educational experience is their relationship with faculty. Research on faculty-graduate student mentoring relationships has provided valuable insights about effective practices that foster the success of graduate students. While these relationships are beneficial to both the mentor and mentee, the literature on faculty-student mentoring relationships primarily has focused either on mentoring relationships with undergraduate students or on specific types of interactions between graduate students and faculty. This article adds to the existing literature by exploring faculty mentors' perceived roles and responsibilities in their mentoring relationships with their graduate students. Data were drawn from interviews with 15 underrepresented faculty members from one research university. Findings reveal that faculty-graduate student relationships can be described by three broad descriptors that characterize participants' roles and responsibilities-faculty members as Allies, Ambassadors, and Master-Teachers. 2011 Springer Science+Business Media B.V.