In the present study, an analysis of shear correction factors is carried out for a homogeneous polyethylene thermoplastic cantilever beam which is reinforced by steel fibers with a rectangular cross-section. An applied shear force produces extension-shear coupling which has not been considered in previous out-of-plane shear deformation studies of beams. The shear correction factor is defined taking into account the coupling effect. Normal and shear stress distributions, as well as shear strain cross section of the rectangular solid beam are obtained analytically. The variation of shear correction factors versus ply angle for the composite beam is also presented.