Nanotoxicity an emerging concept, is receiving increasing attention with the fast development of nanotechnology. Increasing application of nanotechnology highlights the need to clarify nanotoxicity. Plants need to be included to develop a comprehensive toxicity profile for nanoparticles. Toxic potential of three different metal oxide nanoparticles viz., Zinc oxide (ZnO), Aluminum oxide (Al2 O3 ) and Titanium oxide (TiO2 ) were investigated using maize as test plant through germination study. A significant toxic effect was observed on growth parameters like germination percentage, vigour index, shoot and root length of maize. Among the tested concentrations of three different metal oxide nanoparticles, the concentration of 2000 mg L-1 displayed highest toxic effect followed by 1000 mg L-1.   The toxic effect of metal oxide nanoparticles was in the order of ZnO>TiO2 >Al2 O3