A tri(ethylene glycol)-containing lactide analogue was synthesized via thiol-ene chemistry between a bifunctional triethylene glycol and allyl lactide. Subsequent tin octoate catalyzed ring opening polymerization yielded well poly(lactide)-graft-poly(ethylene glycol) copolymers with molecular weights of 6 x 10(3) g/mol and polydispersity indices of 1.6. The tri(ethylene glycol) chains along the copolymers contain azide termini that are capable of efficient postpolymerization functionalization. The utility of this strategy was demonstrated via successful Staudinger ligation to install the Gly-Arg-Gly-Asp-Ser (GRGDS) peptide.