Abstract: Signal transducers and activators of transcription 3 (STAT3) is a transcription factor involved in a variety of biological functions, which conducts extracellular signals to the nucleus, thus activating transcription of target genes. Abnormal activation of STAT3 induces tumorigenesis and promotes tumor development. It has been shown to be an attractive anticancer target. Currently, studies on STAT3 inhibitors are developing rapidly, mainly including STAT3 upstream signal inhibitors and STAT3 direct inhibitors. Recent research progress in anti-tumor activities of drugs targeting STAT3 has been reviewed in this paper.