The response of metal matrix composites is affected by factors such as inclusion distribution and shape, inclusion/matrix interfacial bond, residual stresses, and fabrication-altered in situ matrix properties. These effects are studied using a finite-volume micromechanics model whose extensive modeling capabilities are sufficient to account for these diverse factors. A consistent micromechanics-aided methodology is developed for extracting the unknown in situ matrix plastic parameters using a minimum amount of experimental data. Subsequent correlation of the micromechanics-based predictions with carefully generated data on off-axis response of unidirectional boron/aluminum composite specimens under tensile and compressive axial loading validates the model’s predictive capability and quantifies the importance of each factor.