Nanosized zinc tin oxide (ZTO, Zn2SnO4) photocatalysts were prepared with a hydrothermal technique and their structural and optical properties were characterized by performing powder x-ray diffraction (XRD), ultraviolet-visible (UV-Vis) and photoluminescence (PL) spectroscopies, respectively. The XRD results indicated that the ZTO nanoparticles have a face-centered cubic spinel structure and the average crystallite size was calculated as 18.75 nm by using the Debye-Scherrer equation. The band gap of ZTO nanoparticles was determined as 3.87 eV which is higher than that of bulk ZTO (3.6 eV). The effect of some parameters (amount of dye, amount of catalyst and temperature) were studied on the photocatalytic activity of ZTO nanoparticles. The obtained all results revealed that ZTO nanoparticles can be used as promising photocatalysts for degradation methyl-blue (MB) (dye). Moreover, it was determined that photocatalytic degradation kinetics of dye at all temperatures are better matched to the first order kinetic model.