In this paper, the tensile strength and rupture energy of hybrid poly(methylvinylsiloxane) composites reinforced with short PET fibers and wollastonite whiskers have been studied. It was observed that for a fixed fiber volume fraction, the tensile strength and rupture energy of the hybrid composites first decreased and then increased with wollastonite whisker volume fraction. Analyses of the fiber efficiency factor for the strength and rupture energy of the composites indicated that the fiber pull-out force and pull-out energy were changed as a result of the incorporation of wollastonite. The hybrid reinforcing mechanism is also discussed in this paper.