This paper reports on the influence of deposition temperature on structure and morphology of uncapped Ni2MnIn Heusler films grown by molecular beam epitaxy on InAs(0 0 1). Deposition temperatures between 80 and 360 °C and layer thicknesses between 20 and 100 nm have been used. Our studies reveal that during growth beyond 80 °C an intermixing layer arises at the Heusler/substrate interface that is formed by diffusion of arsenic from the substrate. The intermixing process, which is found to take place via interstitial sites, becomes increasingly severe with increasing growth temperature. Furthermore, we find that the films grown at 80 °C are polycrystalline with crystallites in the B2 phase. At 250 °C the films are found to be single-crystalline and pseudomorphically strained in the B2 phase. The desired L21 phase and single-crystalline Heusler films are observed at a growth temperature of 300 °C. Interestingly, Heusler films in L21 phase are found to have a (1 1 0) surface orientation in contrast to the InAs(0 0 1) substrate crystal. At temperatures higher than 300 °C, strong intermixing and a morphological degradation of the L21 Heusler films is observed.