The present work adopts the synergistic effect of improving concrete radiation shielding using three different nanoparticles. This research aims to add single or hybrid nanoparticles, i.e., nano-silica, ceramic, and metakaolin (NS, NC, and NMK), to normal-weight concrete to reduce the effect of gamma radiation. The weight percentages of nanomaterials as a cement replacement were 3% NS, 6% NC, and 2% NMK. Two combinations of nanoparticles, namely, 3% NS + 2 %NMK and 3% NS + 6% NC, were made to examine the synergistic effect of the present hybrid nanoparticles. Irradiated specimens were exposed to a source of Cobalt 60 (Co−60) for 250 days at a rate of 2 Mrad/day. Adding single or hybrid nanoparticles to concrete improved its compressive, tensile, and flexural strength. After exposure to gamma radiation, the residual compressive strength of different concrete types ranged between 63% and 73%. The microstructural characterizations of un-irradiated and radiated showed that concrete with hybrid nanoparticles had a high radiation shielding due to a significant decrease in the percentage of pores.