Nano-sized cerium dioxide (CeO ) particles are emerging as an environmental issue due to their extensive use in automobile industries as fuel additives. Limited information is available on the potential toxicity of CeO nanoparticles (NPs) on terrestrial invertebrates through dietary exposure. In the present study, the toxic effects of CeO NPs on the model soil organism Porcellio scaber were evaluated. Nanotoxicity was assessed by monitoring the lipid peroxidation (LP) level and feeding rate after 14-days exposure to food amended with nano CeO . The exposure concentration of 1000 μg of CeO NPs g dry weight food for 14 days significantly increased both the feeding rate and LP. Thus, this exposure dose is considered the lowest observed effect dose. At higher exposure doses of 2000 and 5000 μg of CeO NPs g dry weight food, NPs significantly decreased the feeding rate and increased the LP level. Comparative studies showed that CeO NPs are more biologically potent than TiO NPs, ZnO NPs, CuO NPs, CoFe O NPs, and Ag NPs based on feeding rate using the same model organism and experimental setup. Based on comparative metal oxide NPs toxicities, the present results contribute to the knowledge related to the ecotoxicological effects of CeO NPs in terrestrial invertebrates exposed through feeding.