SALL4 (split-like protein 4) is a member of the mammalian homologs of the Drosophila homoeotic gene spalt (sal) and acts as a zinc finger transcription factor to govern the self-renewal and pluripotency of embryonic stem cells. SALL4 expression gradually decreases during development and is even absent in most adult tissues. However, increasing evidence suggests that SALL4 expression is restored in human cancers and its aberrant expression is associated with the progression of many hematopoietic malignancies and solid tumors. The potent roles of SALL4 in regulating cancer cell proliferation, apoptosis, metastasis, and drug resistance have been reported. SALL4 plays a dual role in epigenetic modulation by acting as either an activator or a repressor of its target genes. Furthermore, SALL4 interacts with other partners to control the expression of many downstream genes and the activation of various key signaling transduction pathways. SALL4 is considered as a promising diagnostic and prognostic biomarker and therapeutic target for cancer. In this review, we highlighted the major advances in the roles and mechanisms of SALL4 in cancer and the therapeutic strategies for targeting SALL4 to treat cancer.