The Mg(58)Cu(28.5)Gd(11)Ag(2.5) bulk metallic glass composites (BMGCs) dispersion strengthened by porous Mo particles with different volume fractions and particle sizes were synthesized by casting and characterized. The presence of porous Mo particles could restrict the shear band propagation. It was found for a given volume fraction of Mo particles, smaller particles would lead to more interfacial areas, shorter inter-particle free spacings, smaller confinement zone sizes than the larger particles, and consequently the improvement of compression plasticity from 10% up to 27%. Also, for a given Mo particle size, higher volume fraction would lead to larger compression plasticity. The inter-particle free spacing, as well as the confinement zone size (mean free path of shear bands), appears to be the controlling factor in limiting the propagation of shear bands which in turn affecting the plasticity of BMGCs. (C) 2011 Elsevier Ltd. All rights reserved.