Beta-cyclodextrin (β-CD) stabilized cerium oxide nanoparticles (β-CD@CeO 2 NPs) were synthesized through a hydrothermal route. The electronic properties, surface functional group, surface composition, size, and morphologies of the as-synthesized β-CD@CeO 2 NPs were characterized using UV−visible spectroscopy, FTIR analysis, high resolution X-ray photoelectron spectroscopy (HRXPS), high resolution transmission electron microscopy (HRTEM), and field emission scanning electron microscopy (FESEM). The pH-dependent variation of the ζpotential of β-CD@CeO 2 NPs and the catalytic activity of the NPs for the hydrolysis of paraoxon were investigated. The observed pseudo-first-order rate constant (k obs ) for the hydrolysis of paraoxon is increased with increasing pH and the ζ-potential of β-CD@CeO 2 NPs. The kinetics and mechanism of hydrolysis of paraoxon in the aqueous and cationic micellar media have been discussed.