Effect of Fe doping on structural, optical and magnetic properties of the (In1-xFex)(2)O-3 films (0 <= x <= 0.31) are investigated systematically by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS), UV-Vis, Hall effect and magnetic measurements. Combining XRD, XPS and EXAFS measurements, it reveals that Fe dopant ions substitute for In3+ sites of In2O3 lattice with a mixed-valence (Fe2+/Fe3+) in the (In1-xFex)(2)O-3 films with low Fe concentration (x <= 0.16), while a part of Fe atoms form the precipitate of Fe metal clusters in the (In1-xFex)(2)O-3 films with high Fe concentration (x >= 0.22). The decreased transmittance and optical band gap of films with Fe doping is ascribed to sp-d exchange interaction associated with the Fe dopants. Magnetic characterizations show that all the films display a clear room-temperature (RT) ferromagnetic behavior. The saturated magnetization (M-S) increases monotonically with the increase of Fe concentration and reaches 85.5 emu/cm(3) for the (In0.69Fe0.31)(2)O-3 film. However, the Hall measurements show that the carrier concentration n(c) decreases monotonically with Fe doping, implying that the ferromagnetism is not mediated by carriers in the (In1-xFex)(2)O-3 films (x <= 0.16). It can be concluded that oxygen vacancies play an important role in activating the observed intrinsic RT ferromagnetism in the (In1-xFex)(2)O-3 films (x <= 0.16). However, the larger M-S in the (In1-xFex)(2)O-3 films (x >= 0.22) should be partially due to precipitated Fe metal clusters. (C) 2014 Elsevier B.V. All rights reserved.