SummaryWhile bortezomib has significant benefits in multiple myeloma (MM) therapy, the disease remains incurable due to the invariable development of bortezomib resistance. This emphasises the need for advanced models for preclinical evaluation of new therapeutic approaches for bortezomib‐resistant MM. Here, we describe the development of an orthotopic syngeneic bortezomib‐resistant MM mouse model based on the most well‐characterised syngeneic MM mouse model derived from spontaneous MM‐forming C57BL/KaLwRij mice. Using bortezomib‐resistant 5TGM1 cells, we report and characterise a robust syngeneic mouse model of bortezomib‐resistant MM that is well suited to the evaluation of new therapeutic approaches for proteasome inhibitor‐resistant MM.