In this study, ring-opening polymerization of glycidyl phenyl ether (GPE) is performed using tetra-n-butylammonium acetate (n-Bu4NOAc) as a metal- and halogen-free initiator. Various alcohols are used as chain transfer agents (CTAs), of which ethanol yields oligo-GPE with a controlled number-average molecular weight (M-n) of relatively narrow polydispersity (M-w/M-n = 1.27-1.33). This polymerization system facilely affords various functional oligomers, including amphiphilic block copolymer, reactive oligomer, and branched oligomer from poly(ethylene glycol) methyl ether, allyl alcohol, and polyhydric alcohol as the respective CTAs. The terminal chain structures are confirmed via NMR and MALDI-TOF MS analysis.