Pure and Nd3+-doped tin oxide (SnO2) nanoparticles have been prepared by the sol-gel method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM, energydispersive spectroscopy and UV-visible spectroscopy. The XRD patterns of all the samples are identified as tetragonal rutile-type SnO2 phase which is further confirmed by TEM analysis. Neodymium doping introduces band gap narrowing in the prepared samples and enhances their absorption towards the visible-light region. The photocatalytic activity of all the samples was evaluated by monitoring the degradation of methylene blue solution under day light illumination and it was found that the photocatalytic activity significantly increases for the samples calcined at 600 than 400 °C, which is due to the effective charge separation of photogenerated electron-hole pairs. The efficiency of photocatalysts was found to be related to neodymium doping percentage and calcination temperature. © 2016 Indian Academy of Sciences.