Objectives: Cancer affects both patients and their families. Sometimes, the effects of cancer on families are greater than its effects on patients. Family caregivers play significant roles in care for patients with cancer. Nonetheless, the data on the challenges they face in caregiving are limited. The present study explored the perspectives of patients with gastric cancer (GC), their family caregivers, and healthcare providers regarding family caregivers' challenges in caregiving to patients with GC. Methods: This descriptive exploratory qualitative study was conducted in 2019-2020. Six GC patients, six family caregivers, three physicians, and five nurses took part for a total of twenty participants. Purposive sampling was performed, and data were collected through semi-structured interviews and continued up to data saturation. Conventional content analysis was used for data analysis. Results: Caregivers' challenges in caregiving to patients with GC were grouped into five main categories, namely, lengthy process of GC diagnosis, delivery of bad news, management of physical symptoms, altered relationships, and psychological consequences, and 14 subcategories. Conclusion: Educating the public about the primary symptoms of GC and the importance of timely seeking medical care as well as using culturally appropriate protocols for delivering bad news is recommended. Empowering family caregivers for the effective management of GC symptoms and caregiving-related challenges are also recommended to reduce their caregiver burden.