Comparative study of S-Alkylation of thiophenol under Liquid-Liquid (L-L) biphasic versus Liquid-Liquid-Liquid (LL- L) triphasic phase transfer catalysis (PTC) has been carried out. Various alkyl halides were used as an alkylating agent. Tetrabutyl ammonium bromide (TBAB) was used as Phase transfer catalyst. The rates of reaction were enhanced under the Liquid-Liquid-Liquid triphasic PTC as compared to the Liquid-Liquid biphasic PTC.