Abstract: Squalene monooxygenase (SQLE) is the rate-limiting enzyme of cholesterol biosynthesis. It plays a crucial role in regulating cholesterol homeostasis. Increasing evidence shows that SQLE is closely related to the occurrence, development, metastasis, and poor prognosis of various cancers. SQLE can not only promote the proliferation of cancer cells and epithelial-mesenchymal transformation but also play an important role in maintaining the stemness of cancer stem cells and regulating cholesterol homeostasis. SQLE may be a potential molecular target for cancer therapy. In this review, the role of SQLE in regulating cholesterol homeostasis in vivo; its function in the occurrence, development, and metastasis of various cancers; and its molecular mechanism were summarized. Screening new SQLE inhibitors may provide new ideas for targeted cancer therapy.