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Thermal oscillations in oxalic acid-bromate-MnSO 4 -H 2 SO 4 -acetone system have been studied in aqueous solution of nonionic surfactants, Tweens (20, 40, and 60), and Brijs (56, 58 and 76). It has been observed that significantly low concentration of the surfactants can inhibit the oscillatory reaction. In general, they have inhibitory effects on the frequency and enthalpy of oscillations. The inhibition has been found to have direct dependence on the length of the nonpolar tail of the surfactant molecule. There is a threshold concentration for a surfactant above which oscillation stops, and this threshold or critical concentration decreases with increasing length of the surfactant chain. The amphiphile n-heptanol has also shown significant inhibitory effect.