Caused by legal regulations for future engine systems, which are getting severe, especially related to the emission of carbon dioxide (CO2), the automotive industry is enforced following the strategy of downsizing their conventional combustion engines. Therefore, engines of low cubic capacity are supercharged by means of exhaust turbochargers. The increased effectiveness of the engine leads to a reduction of the fuel consumption and pollutant emission. In operation, turbocharger turbine wheels are exposed to high temperatures and high mechanical loads. The low density of intermetallic γ-titanium aluminide (γ-TiAl) alloys when compared to the so far used Ni-base superalloys as well as their balanced mechanical properties make these alloys to attractive alternatives. A reduced weight of the turbocharger rotor enhances the response behaviour (“turbo-lag”) and this leads to a better effectiveness of the complete system. In this study, a γ-TiAl-based alloy with the nominal composition of Ti-43.5Al-4Nb-1Mo-0.1B (in at%) as turbine wheel material in turbocharger for diesel engines is investigated. The main focus of attention is laid on the determination of the microstructural stability by means of isothermal heat treatments. The results are compared to turbine wheels which were on trial on a hot-gas test facility. Additionally, the oxidation behaviour of the alloy is investigated.