Interferon (IFN)-induced transmembrane protein 1 (IFITM1), a member of the IFN-induced transmembrane protein family, is reported to be highly expressed in tumor tissues as well as cancer cell lines, and it is an independent prognostic biomarker for patients with certain tumor types, such as gallbladder carcinoma, esophageal adenocarcinoma, colorectal cancer, and gastric cancer. Moreover, overexpression of IFITM1 promotes tumor cell proliferation, invasion, metastasis, angiogenesis, and therapeutic resistance, including endocrine therapy, chemotherapy, and radiotherapy resistance. Due to these diverse functions of IFITM1 in tumors, targeting IFITM1 may provide a novel strategy for cancer treatment and be highly desirable to improve cancer patient outcomes. Herein, we decipher the role of IFITM1 in cancer in detail.