Cholangiocytes are the epithelial cells of the biliary system, responsible for the transport and modification of bile. Cholangiocyte disorders, known as cholangiopathies, are a diverse group of life-threatening conditions characterised by cholestasis, ductopenia and eventual liver failure. There are currently no curative treatments for cholangiopathies aside from liver transplantation and while individual cholangiopathies are rare, together they account for a third of adult and 70% of paediatric liver transplants. There is a scarcity of suitable organs for transplantation, however, so development of cholangiocyte cellular therapies capable of replacing or repairing damaged bile ducts would have significant therapeutic value. The safety of such therapies must be assessed before they are suitable for clinical translation and an essential component of that is an evaluation of immunogenicity. In this dissertation I investigated the immunogenicity of cholangiocyte organoids (COs) from an established system developed within the Vallier lab. I first assessed the survival of COs in vivo and generate CO lines expressing luciferase to allow for real-time bioluminescent imaging in vivo. I characterised the expression of HLA molecules on COs compared to primary cholangiocytes and after exposure to a series of pro-inflammatory environments and demonstrated that expression of HLA molecules is reduced in COs compared to primary cholangiocytes but that exposure to pro-inflammatory cytokines restored high levels of HLA expression. I also showed that physiologically-relevant concentrations of pro-inflammatory cytokines were sufficient to upregulate HLA class II expression on COs. To assess the immunogenicity of COs in a transplant environment I used two humanised mouse models. I demonstrated that these models can induce an immune response against allogeneic COs and compared the response to allogeneic and autologous COs in both models. I identified HLA-matched CO lines and immune cell donors and investigated the impact of HLA-matching on the immunogenicity of CO allografts in a humanised mouse model. Overall, the work presented in this dissertation advances the understanding of the immunogenicity of cholangiocyte organoids, both in terms of their expression of immunogenic antigens and the response towards COs within both an allogeneic and autologous transplantation setting.