Health care providers routinely advise cancer patients to involve support persons in oncology care to fulfill critical support roles. This qualitative descriptive study explored alignment of triadic perceptions of support person involvement in oncology treatment visits and cancer-related care from the perspectives of patients with gynecologic cancer ( n = 18), regular visit-attending support people ( n = 16), and health care providers ( n = 10), including oncologists, nurses, and medical assistants. Semi-structured interviews ( N = 44) captured perceptions of facilitation and interference of support persons' roles within and outside appointments with oncology providers. Thematic analyses revealed alignment and divergence regarding support persons' instrumental, informational, and emotional support behaviors. Perspectives aligned regarding what support functions companions provide. However, patients and support persons emphasized the significance of instrumental followed by informational and emotional support, whereas oncology providers highlighted informational, followed by emotional and instrumental support. Discussion provides insight into each role’s perspective in the triad.