This work was aimed at characterizing the effects of foliarly applied rutile (TiO2) nanoparticles (NPs) on Ti translocation as well as biomass production and antioxidant system in tomato (Solanum lycopersicum L.). The seeds were germinated and grown on a substrate in individual pots in a growth chamber. The TiO2 NPs were characterized using transmission electron microscopy (TEM), Raman spectroscopy, dynamic light scattering (DLS), and laser doppler velocimetry (LDV). Titanium dioxide NPs had a rod-shaped form and were moderately prone to agglomeration. The TiO2 NPs treatments were applied at 0, 5, 10, 20, 40, 80, and 160 mg L−1 by foliar spraying on 20-day-old S. lycopersicum plants. After 7 days of treatment exposure, tissue Ti concentration was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Nanoparticle treatments increased tissue Ti concentration; Ti was translocated from leaves to stem, triggering a significant decrease in biomass production. With respect to the control, an increase in total reducing capacity (1.7-fold), antioxidant activity (1.5-fold), and superoxide dismutase activity (2-fold) were observed in the treatments with intermediate to high doses. The TiO2 NPs triggered an increase in tissue Ti concentration, increasing the antioxidant system activity and lipid peroxidation at low to intermediate doses, and decreasing biomass production at intermediate to high doses.