The effect of intrinsic and extrinsic factors on the measured results, such as load-displacement curves and interfacial stresses, from indentation tests of composite materials is studied using both analytical and finite element models. The intrinsic factors include properties of the fiber-matrix interface and the material symmetry of the fiber (transversely isotropic or isotropic). The extrinsic factors include the radius of the hole through which the fiber is pushed in, and the size and shape of the indentor. Out of the above factors, only the radius of the hole is found to have a negligible effect on the results of the indentation test.