Hydrogen-fuelled internal combustion engines represent a promising solution for the decarbonization of road transport, benefiting from favourable combustion properties such as high flame speed and wide flammability limits, which enable high-efficiency engine operation and extended lean-burn capabilities. To support the development of hydrogen internal combustion engines while limiting experimental effort, numerical simulation represents a valuable tool for engine performance prediction, virtual calibration, and system-level analysis across a wide range of operating conditions, thus limiting extensive and costly experimental campaigns. Within this framework, this thesis, made in collaboration with Westport Fuel Systems, focuses on the development of a complete 0D/1D model of a turbocharged hydrogen-fuelled internal combustion engine, developed in the commercially available software GT-SUITE.