This study evaluates the effect of zinc oxide nanoparticle (ZnONP) on permanent deformation of modified bitumen. The moisture susceptibility was also evaluated in hot-mix asphalt (HMA) prepared by nano-ZnO modified bitumen. Bitumen modification was conducted using a high shear mixer at contents of 1%, 3%, and 5% by weight. Permanent deformation was evaluated using the $G^{*}/\sin \delta$ parameter obtained from dynamic shear rheometer (DSR) test results for modified bitumen. Compaction was conducted by a Superpave gyratory compactor, and moisture susceptibility was using the modified Lottman procedure. The dispersion of nanomaterials was analyzed by scanning electron microscopy (SEM). The best performance was obtained by ZnONP 5% modification. The performance grade was determined as PG 64-22 after all modifications. Optimum bitumen content (OBCs) were decreased by modification except the 1% mix (which had the same results as the reference sample). Asphalt mixtures were found to be highly resistant against moisture for all nanomodifications. Lower performance was determined just for the 1% ZnONP modified HMA as compared to the reference sample. After SEM analysis, the dispersion of nanomaterials in the mixture was homogenous. Up to 4 μm agglomeration was displayed in the mix.