Treating Kevlar fabric with nanoparticles is known to augment its mechanical properties due to increased inter-yarn friction. Previous studies on silica nanoparticle-treated Kevlar (SNK) show improved ballistic performance. It is therefore of interest to explore the influence of nanoparticle size, shape, and material in this context. In this study, first, quasi-static in-plane and out-of-plane yarn pullout tests were conducted on neat and SNK fabrics using customized experimental rigs. A colloid-based process is used to impregnate dry nanoparticles into plain woven Kevlar K745 fabric. Factors such as treatment level, transverse pretension, pullout rate, and yarn direction are considered and the pullout force versus displacement history is recorded to extract critical features. Broadly, for all cases, the initial bilinear stiffness regimes seen for the neat fabric transition to nonlinear and higher values and pullout regime stiffness also increases slightly at higher treatment levels, pretensions, and rates. Peak pullout force increased by at least 700 % for the 40 wt% treated case vis-à-vis the neat case. Weft yarn direction pullout is slightly more compliant with lower peak load compared to warp owing to its lower waviness. Ballistic impact tests were performed on 3-layer samples of neat, and 30 wt% treated fabric for different nanoparticle sizes, shapes, and materials using a custom small-caliber gas-gun rig. The energy absorbed has a positive linear correlation with particle size in the 10-80 nm range for SNK, while alumina and zinc oxide nanoparticles of comparable size display lower energy absorption. At the length scales considered, using cylindrical nanoparticles did not affect energy absorption likely due to particle agglomeration which is borne out in SEM imaging. Additionally, damaged zone areas estimated from sample back-face images correlate well with absorbed energy across all samples. Specific energy absorption for the 30 wt%, 80 nm SNK was more than three times that of its neat counterpart indicating higher velocity projectiles can be defeated without significant weight penalty. Further investigations could lead to nanoparticle-treated flexible armors that not only enhance ballistic protection, but also incorporate multifunctional capabilities such as wearable electronics, wound coagulation, or adaptive camouflage.