Gastric and gastro-esophageal cancers (GC/GEJ) appear as the second cancer-related death worldwide. Diagnosis is made at an advanced stage offering a curative attempt in less than 50% of cases. Despite the improvements of the systemic cytotoxic chemotherapy regimens, the prognosis of patients with metastatic GC/GEJ cancer remains poor. Recent insights in biochemical pathways have permitted to identify potential targets. The extracellular domain of HER2 receptors is implicated in cells’ proliferation and in the anti-apoptotic process occurring in GC/GEJ cancers. Trastuzumab, a monoclonal antibody targeting HER2, in addition to chemotherapy permitted to obtain more than one year of survival in HER2-positive advanced GC/GEJ cancers. Recently, ramucirumab, a humanized monoclonal antibody targeting VEGFR-2 receptor demonstrated its efficacy as a second line treatment for patients with advanced GC/GEJ cancer. These encouraging results have justified evaluating targeted therapies in GC/GEJ cancers. In this review, we summarize targeted therapies that might present clinical efficacy in the treatment of advanced GC/GEJ cancers.