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Abstract Glucagon-like peptide 1 receptor (GLP-1R) agonist is an emerging anti-diabetic medication whose effects on the risk and progression of cholangiocarcinoma (CCA) are controversial. This study aimed to elucidate the roles of GLP-1R and its agonists on intrahepatic CCA (iCCA) progression. Expressions of GLP-1R in iCCA tissues investigated by immunohistochemistry showed that GLP-1R expressions were significantly associated with poor histological grading (P = 0.027). iCCA cell lines, KKU-055 and KKU-213A, were treated with exendin-4 and liraglutide, GLP-1R agonists, and their effects on proliferation and migration were assessed. Exendin-4 and liraglutide did not affect CCA cell proliferation in vitro, but liraglutide significantly suppressed the migration of CCA cells, partly by inhibiting epithelial-mesenchymal transition. In contrast, liraglutide significantly reduced CCA tumor volumes and weights in xenografted mice (P = 0.046). GLP-1R appeared downregulated when CCA cells were treated with liraglutide in vitro and in vivo. In addition, liraglutide treatment significantly suppressed Akt and STAT3 signaling in CCA cells, by reducing their phosphorylation levels. These results suggested that liraglutide potentially slows down CCA progression, and further clinical investigation would benefit the treatment of CCA with diabetes mellitus.