The interactions of reactively sputtered titanium carbide (TixC) films with Si, SiO2, Ti, TiSi2, and Al have been studied using Auger electron spectroscopy, x‐ray diffraction, and four‐point probe resistance. The TixC films react with Si leading to silicide phases that are not observed when pure Ti reacts with Si. The interaction of TixC with Si is delayed to higher temperatures with increasing carbon content. Forx≤1, no interaction is observed even after 900 °C‐30 min anneal. Forx≥1, the silicide formation leads to phase separation with TiSi2near the silicon substrate plus an outer titanium carbide layer, which, like all other TixC films investigated, is found to be an effective diffusion barrier to Al penetration up to 500 °C. Forx≤1, no interaction with SiO2is observed up to 900 °C. However, Ti‐rich films interact with SiO2to form titanium oxide. The stoichiometric film adheres to Ti and TiSi2much better than to Si and SiO2. It does not react with Ti or TiSi2up to 750 °C. At 900 °C TiC is unstable on TiSi2.