Objectives: A systematic review and qualitative synthesis was undertaken to deduce requisite knowledge, skills and attributes of cancer support group leaders. Methods: Medline, CINAHL, and PsychINFO databases were used to identify relevant literature. Inclusion criteria were made deliberately broad after pilot searches produced too few documents and included: adult group leaders who were volunteers, peers or professionals; published in English from database inception to February 2014. Data was extracted on: year of publication; country of authors’ origin; study design (if relevant) and methods; group type and group leadership; sample description; and leader qualities. Results: Forty-nine documents met inclusion criteria. Fourteen reported on cancer groups, 31 on non-cancer groups (including four mixed groups) and four did not specify group type. Seven qualities were deduced including group management, group process, role modelling, awareness, willingness, agreeableness, and openness. These were consistent across group type and group leadership. Conclusions: Findings may be relevant to a general model of peer group support and can inform the development of a practical and realistic minimum standard for support group leadership in healthcare. Practice implications: Results can be used to help cancer agencies manage relationships with group leaders. Knowledge of requisite qualities may inform selection, training and support.