Gastric cancer (GC) is one of the most common types of cancer and is associated with relatively low survival rates. Despite its considerable burden, there is limited guidance for Canadian clinicians on the management of unresectable metastatic GC and gastroesophageal junction cancer (GEJC). Therefore, we aimed to discuss best practices and provide expert recommendations for patient management within the current Canadian unresectable GC and GEJC landscape. A multidisciplinary group of Canadian healthcare practitioners was assembled to develop expert recommendations via a working group. The often-rapid progression of unresectable GC and GEJC and the associated malnutrition have a significant impact on the patient’s quality of life and ability to tolerate treatment. Hence, recommendations include early diagnosis, identification of relevant biomarkers to improve personalized treatment, and relevant support to manage comorbidities. A multidisciplinary approach including early access to registered dietitians, personal support networks, and palliative care services, is needed to optimize possible outcomes for patients. Where possible, patients with unresectable GC and GEJC would benefit from access to clinical trials and innovative treatments.