The radiation response of nanostructured materials is of great interest because of the potential of nanoscale materials design for mitigating radiation damage. We report a greatly enhanced resistance to radiation-induced amorphization in nanocrystalline ${\text{Gd}}_2{\left({\text{Ti}}_{0.65}{\text{Zr}}_{0.35}\right)}_2{\text{O}}_7$ at a particle size less than 20 nm while larger crystals with the size $>100\text{nm}$ are radiation sensitive. The grain size of pyrochlore, ${\text{Gd}}_2{\left({\text{Ti}}_{0.65}{\text{Zr}}_{0.35}\right)}_2{\text{O}}_7$ , can be controlled by mechanical milling and subsequent thermal treatment (from 800 to $1500°\text{C}$ ), offering the possibility of designing pyrochlore materials at the nanoscale with enhanced performance for specific radiation environments.