<p>This study investigates the effects of graphene oxide nanoplatelets (GNPs) and bentonite clay nanoparticles on the rheological behavior of shear thickening fluids (STFs). STFs, which exhibit rapid viscosity increases under shear stress, were formulated using a base suspension of 35% silica nanoparticles in polyethylene glycol (PEG) and reinforced with either 2.5% or 5% GNPs or 2.5% clay. Rheological tests, including shear rate, frequency, and temperature sweeps, were conducted to analyze peak viscosity, critical viscosity, and the crossover points of storage modulus (G') and loss modulus (G''). Results reveal that GNPs significantly enhance the STF’s viscosity and shear sensitivity, with the 5% GNP-reinforced STF demonstrating the highest peak viscosity and lowest shear rates required for thickening, along with superior rigidity. Temperature-dependent testing highlights a marked decrease in viscosity with rising temperatures, attributable to increased molecular mobility. Frequency and strain-dependent analyses show that GNP-reinforced STFs offer greater structural integrity under dynamic loads, with the 5% GNP STF showing a quick transition to fluid-like behavior at higher moduli. This study underscores the value of GNPs, especially at higher concentrations, in tailoring STF properties for applications in impact resistance and adaptive damping.</p> Graphical Abstract <p></p>