Abstract: A generalized self-consistent model to predict the effective longitudinal shear modulus of multiphase fiber composites was developed, by considering the effect of fiber section shape. In the model, combined confocal elliptical cylinder unit cells are embedded in an infinite homogenization composite. By using conformal mapping technique and Laurent series expansion, a close form solution was obtained. Further a group of algebraic equations to predict effective longitudinal shear modulus of multiphase fiber composites were obtained by virtue of the averaged stress-strain theorem. When the shear moduli of all fibers are same, the above equations can be reduced to those for single phase fiber reinforced composites. The validity of the proposed model was verified by comparing present theoretical predictions with available experimental results.