This study aimed to evaluate the effects of titanium dioxide nanoparticles on the salinity tolerance of rice. The effects of five nano titanium dioxide concentrations (0 mg/L, 25 mg/L, 50 mg/L, 75 mg/L, and 100 mg/L) on the physiological and biochemical parameters of rice were evaluated. The results showed that among three rice varieties (ST24, ST25, OM18), only ST25 grew in a better manner with the application of TiO₂ nanoparticles and the optimal concentration of TiO₂ nanoparticles was 50 mg/mL. It increased the shoot height by 20.07% and the survival rate of rice compared to the control. These growth-promoting effects were simultaneous with increased levels of chlorophyll, carotenoid and proline. The activities of antioxidant enzymes were improved. While activities of enzymes catalase and peroxidase increased significantly, no change in the activities of ascorbate peroxidase was observed. Finding of this study showed that titanium dioxide nanoparticles increased the salinity tolerance of rice by promoting the photosynthetic and anti-oxidative processes in rice seedlings.