Background: The caregivers of cancer patients go through numerous changes in their lives, caused by the complexity of cancer care, which then influence their quality of life (QoL). In this context, the sense of coherence (SoC) has been introduced as individuals' capacity to adapt to complex situations. Objectives: This study aimed at examining the relationship between QoL and SoC among the caregivers of cancer patients. Methods: This descriptive correlational study was performed on the caregivers of cancer patients referred to a teaching hospital in Tehran, Iran. In total, 200 eligible caregivers, selected by purposive and convenience sampling from September to December 2022, completed the research instrument comprised of a researcher-made demographic-clinical information form, the SoC Scale (13-item), and WHOQoL-BREF. The data were analyzed by the SPSS 20 software. To investigate the relationship between caregivers’ SoC and QoL, first, the correlation was determined, and afterward, the significant variables were analyzed, using multiple linear regression. Results: The overall mean score of QoL among the caregivers was 52.12 ± 14.45. In this way, the highest and lowest values were associated with the domains of physical health and social relationships, receiving the mean scores of 55.19 ± 11.46 and 38.40 ± 10.08, respectively. The overall mean score of SoC was also equal to 49.71 ± 9.34. As well, the results of the study demonstrated a significant positive correlation between SoC and QoL (r = 0.585, P < 0.001) as well as its 3 domains. Considering the demographic and clinical factors, the regression outcomes revealed that SoC was a predictor of QoL in the caregivers of cancer patients (P < 0.001, Β = 0.65). Among the demographic factors, a significant correlation was accordingly observed between age, marital status, income level, employment status, and QoL and some of its domains (P < 0.05). Conclusions: It was argued that SoC could be a positive predictor and a protective factor for QoL among the caregivers of cancer patients. In this vein, it was recommended to give a boost to the SoC dimensions during oncology and palliative care via an interdisciplinary approach and a variety of interventions. Upon developing QoL in the caregivers, QoL among the cancer patients could be then promoted.