Various nanoparticles have been actively explored as additives in polymer membranes because of their high compatibility with polymers and pore-forming function. Numerous nanoparticles exist in membrane technology, but hafnium oxide (HfO2) nanoparticles have not been studied in ultrafiltration (UF) membranes. In the present study, HfO2 and novel sulfonated HfO2 (SHfO2) nanoparticles were synthesized and incorporated into polyvinylidene fluoride (PVDF) to develop a novel nanocomposite ultrafiltration (UF) membrane. The improved antifouling properties and rejection of the PVDF-HfO2/SHfO2 UF membrane were measured using bovine serum albumin and humic acid as model fouling agents. The SHfO2-incorporated membranes showed excellent properties such as large pore size, porosity, and reduced surface roughness. The SHfO2 nanoparticles were found to have better compatibility with the PVDF polymer. The pure water flux of the PVDF-HfO2 (412.8 L.m(-2) .h(-1)) and PVDF-SHfO2 (557.4 L.m(-2) .h(-1)) membranes was enhanced greatly: 55 and 111% higher than that of the pure PVDF membrane (264.2 L.m(-2).h(-1)), respectively. Moreover, in the antifouling test, the PVDF- SHfO2 and PVDF-HfO2 membranes showed the lowest irreversible fouling of 0.96 and 12.2%, respectively. The sulfonated HfO2 membrane (P-SHfO(2)3) showed up to 94.7 and 90.1% rejection for BSA and HA, respectively. The high water permeability, antifouling properties, and rejection of the PVDF-SHfO2 membrane were attributed to the addition of the more hydrophilic and negative charge group of -SO3H on SHfO2. This resulted in a highly hydrophilic surface and porous structure and may increase the negatively charged surface, which led to improved water flux, antifouling properties, and rejection. The performance of a PVDF- SHfO2 membrane was also compared with the PVDF-sulfonated TiO2 membrane. The overall study demonstrated the potential applications of HfO2 and novel SHfO2 in the preparation of enhanced water flux and antifouling nanocomposite UF membranes for water treatment.