Social support that includes promoting healthy behaviours throughout the oncology pathway, from diagnosis to treatment to survival, can leverage existing support networks and improve the health of patients and family members in supportive roles. This scoping review aimed to identify and summarise the impact of social support on the patient-informal caregiver relationship during cancer treatment. Inclusion criteria were related to a high focus on dyadic cancer patient-informal caregiver relationships, considering a population of adult cancer patients in active hospitalisation on an oncology ward, and published between 2012 and 2022 to get a portrait of the literature that might influence the current practice. A systematic search using the “Population, Concept, and Context” framework was performed in PubMed, Web of Science, SCOPUS, EBSCO Medline, and CINAHL: 13 articles from the 16,425 pre-qualified articles published between 2012 and 2022. The narrative synthesis of the included studies highlighted that social support, encompassing its different forms within the context of dyads, is frequently associated with an enhanced quality of life, hope, and resilience of both patients and informal caregivers. However, it is important to recognize that the support interventions provided to patients, particularly caregivers, were frequently not thoroughly evaluated or explained, and the sample sizes of the included studies were often limited. Therefore, this review clarified the social and clinical potential of social support for the patient-informal caregiver relationship, paving the way for future robust studies that require to be powered and designed on specific outcomes to allow informing the practice on specific recommendations.