The microstructure and thermomechanical properties of Ni thin films were investigated by a range of techniques. The films were 150 1000nm thick and were sputter-deposited onto both oxidised Si (100) and alpha-Al2O3 (0001) substrates. The films deposited onto Si wafers formed a {111} textured columnar microstructure with a mean grain size similar to the film thickness while those on alpha-Al2O3 formed an epitaxial microstructure with two broad, twin-related, alignments with the substrate. Thermomechanical testing with a wafer curvature apparatus indicated that the yield stress of the polycrystalline films increased with decreasing film thickness until a plateau of 1100 MPa was reached, this plateau is attributed to the present experiments exerting insufficient thermal strain to induce yielding in the thinner films. At elevated temperatures the compressive yield in the films shows a competition between dislocation and diffusion controlled plasticity. The room temperature and elevated temperature yield for the epitaxial films increased with decreasing film thickness, showing good quantitative agreement with the Nix-Freund model.