The critical miceller concentrations (cmc) of Aerosol-OT (AOT) in binary mixtures of eucalyptus oil (EO) with butanol (Bu) and cinnamic alcohol (CA) are determined by the methods of calorimetry and fluorometry and are found to be in good agreement with each other. The mixed EO and Bu medium has shown a minimum and a maximum in cmc at 10% and 50% (w/w) of oil, respectively. On the other hand, for the EO/CA mixture, only a maximum is obtained at 50% (w/w) of EO. Enthalpy of micellization of AOT in the former has shown two maxima, one higher at 10% EO and the other lower at 50% EO, whereas in the latter only one maximum at 50% EO is obtained. The entropies of micellization are all positive having fluctuations with composition and do not linearly correlate with the enthalpies. The heat capacities of the resulting binary mixtures have indicated nonideal mixing behavior.