Purpose The purpose of the study was to examine graduate student perspectives on the common and unique roles peer mentors and supervisors play in supporting student success and wellbeing during their program. Design/methodology/approach A qualitative research design involving semistructured interviews with 62 thesis-based masters and doctoral students from four professional faculties, Education, Medicine, Nursing and Social Work, at a large public research-intensive university in Canada. Findings Findings transcend the four disciplines of study. Communities of support are described that involve both supervisors and peers in combination, clusters of meaning by supervisory paradigm are identified and original findings presented that expand upon the learning alliance framework by explicitly considering the role of peer mentors in graduate student success. Research limitations/implications While supervisors bear primary responsibility for fostering effective research-based relationships, this study’s findings strengthen the argument that mentoring and advising of graduate students is most effective when conducted within a collaborative community of support that involves learning alliances among faculty, peers, program staff and academic leaders across the institution. Practical implications A four-pronged approach to graduate education that emphasizes the collective responsibility of institutions, programs, supervisors and students in creating a supportive ecosystem for holistic graduate student academic success and wellbeing is recommended. Social implications Key argument that it is essential to embrace a collaborative and community of support mindset, where multiple stakeholders actively contribute to the wellbeing and academic development of graduate students throughout their programs. Originality/value A cross-disciplinary perspective is offered on the importance of both supervisors and peers in assisting thesis-based graduate students to successfully navigate academic, social and personal journeys through graduate school.