Background and aims Gamma-delta (gamma delta) T cells are involved in the development of diverse liver and autoimmune diseases, whereas the role of gamma delta T cells in primary biliary cholangitis (PBC) remains unclear. Methods We analyzed the number, phenotypes, and functional molecules of both circulating and hepatic gamma delta T cells in PBC patients and healthy controls (HCs) by flow cytometric analysis and immunohistochemistry. Results We identified two distinct functional subsets of circulating gamma delta T cells according to the CD3/TCR gamma delta complex: the TCR gamma delta(high) and TCR gamma delta(low) subsets. Approximately, three-quarters of cells in the TCR gamma delta(high) subset were V delta 1 T cells, while V delta 2 T cells were enriched in the TCR gamma delta(low) subset in HCs. The frequency and absolute number of circulating TCR gamma delta(low) cells were significantly decreased in PBC patients compared with HCs (p < 0.001). Furthermore, the frequency of TCR gamma delta(low) cells was correlated with disease severity and ursodeoxycholic acid (UDCA) response. TCR gamma delta(low) cells exhibited a similar apoptotic and proliferative phenotype, but enhanced liver-homing chemokine receptor (CXCR6) expression in PBC patients compared with HCs. In addition, circulating TCR gamma delta(low) cells were more activated and produced higher granzyme B (GZMB) in PBC patients compared with HCs. Finally, compared with heathy liver controls, hepatic gamma delta T cells were increased and infiltrated in the inflamed portal tracts in PBC liver. Furthermore, the number of hepatic gamma delta T cells was correlated with cholestatic markers and UDCA response. Conclusion The circulating TCR gamma delta(low) subset may migrate to the liver via the CXCR6-CXCL16 axis and be involved in the pathogenesis of PBC by increasing GZMB production.