Microwave irradiation has been used to intensify the alkylation reaction of phenol with tert-butyl alcohol using ion-exchange resin as the catalyst. About 86% conversion of phenol is obtained in 4 min under microwave irradiation. The major products are ortho-tert-butyl phenol (o-TBP), para-tert-butyl phenol (p-TBP) and 2,4-di-tert-butyl phenol (2,4-DTBP). o-TBP predominates in the product mixture as the kinetically favored product in shorter reaction times, but p-TBP is the major product for longer reaction times. The selectivity toward ortho-or para-substituted phenols can be manipulated by controlling the exposure time of the reaction mixture to the microwave irradiation. The Langmuir-Hinshelwood-Hougen-Watson (LHHW) surface reaction controlled model was used for the kinetic data analysis.