<p>This study investigates the effective elastic properties, yield strength, and elastoplastic behavior of a biphasic composite as a function of the geometry and spatial distribution of its inhomogeneities. The composite consists of a metallic matrix exhibiting von Mises plasticity with nonlinear isotropic hardening, within which identical, linear, and isotropic spherical or spheroidal inhomogeneities are perfectly embedded. The effective response is analyzed under macroscopic uniaxial, biaxial and shear loading conditions. The main contribution lies in the application of the Mori–Tanaka homogenization scheme to predict the mechanical properties and the elastoplastic behavior of the biphasic composite with both oblate and prolate inhomogeneity geometries, as well as to assess the effect of misalignment. It is also demonstrated, using the equivalent inclusion method, that the total strain inside a spheroidal inhomogeneity with vanishing stiffness is equal to the eigenstrain.</p>