Introduction: The Hedgehog (Hh) pathway serves as a major regulator in organ development, stem cell maintenance, cell proliferation, and cell differentiation. This pathway is highly regulated and aberrant activation will promote tumorigenesis. Hh pathway notably Sonic Hedgehog pathway was reported to be upregulated and promote tumorigenesis in various human malignancies including colorectal, gastric, lung, prostate, and breast. This review was aimed to discuss the current understanding of Hh pathway activation in different types of human cancers and discuss the development of the therapeutic applications targeting Hh pathway. Methods: A systematic review was conducted using the electronic research database PubMed Central (PMC) from 2014-2019. The search was limited to studies that are relevant to both Hh signalling pathway and human cancers. A total of 50 articles were selected and their references cited were searched and reviewed. Results: The results regarding the role of Hh signalling in pancreatic cancer and colorectal cancer are controversial with some reporting tumor promoting activities whereas others tumor suppressive activity. Besides, results from other studies suggesting that Hh signalling pathway plays an oncogenic role by inducing tumor cells proliferation, promoting metastasis and maintaining cancer stem cells in human cancers such as lung, stomach, and breast. To date, Glasdegib (PF-04449913) is the only Hh targeting small molecule inhibitor being studied at FDA Phase 3 clinical trial. Identification of the right tumors and minimization of the side effects remain as the main obstacles in the development of Hh signalling inhibitors. Conclusion: In conclusion, advancement in our understanding of Hh pathway has provided us opportunity to develop novel therapeutic strategies to fight human cancers with activated Hh pathway but more studies need to be conducted to solve the controversial regarding the role of Hh pathway in certain cancers.