The effect of layered-silicates on the mechanical response of intercalated polycarbonate (PC) nanocomposites subjected to quasi-static tensile, compressive and ballistic impact testing conditions has been investigated. These nanocomposites were melt-processed, in which good dispersion of nanoclays and adequate adhesive bonding between the nanoclay and PC matrix are achieved. However, their ductility upon tensile loading is significantly affected; a transition from ductile to brittle deformation occurs at clay loading of about 3 wt.%. Stress whitening is evident in the tensile- and ballistic-tested 1.5, 2.5, and 3.5 wt.% clay nanocomposites, and is attributed to the light scattering by microvoids, which are presumably formed from either crazing of PC or debonding of the nanoclay tactoids upon mechanical deformation. The effect of clay loading on the ballistic impact strength of the monolithic PC nanocomposites and layered PC/PC-nano/PC composites is determined. Compressive yield strength measurements are obtained at strain rate of 0.001/s for the monolithic PC nanocomposites and are utilized to correlate with the ballistic impact strength of the layered PC/PC-nano/PC composites. Thermal degradation is noted in these PC nanocomposites, and its effect on the mechanical deformation is briefly discussed.