Over the past 10 years, polyglycerols and their structurally related analogs have received considerable attention in the biomedical field. Poly(glycidyl methacrylate) (PGMA) is a versatile polymer because its pendant epoxide groups can be opened with different functional groups to generate poly(glycerol methacrylate)s (PGOHMA) derivatives. In this work, linear and star-shape PGMAs were synthesized by atom transfer radical polymerization and then functionalized with four different amines by ring-opening addition. This resulted in the formation of polyglycerol-like polymers having both hydroxyl and amine moieties and different water-solubility. The water-insoluble polymers could form pH-sensitive nanoassemblies, while the soluble derivatives efficiently complexed a short strand polynucleotide. The aminated polyglycerol interacted more avidly with the oligonucleotide than the control poly(ethyleneimine), and high transfection efficacy could be obtained with the linear derivative. Such polymers could find practical applications for the delivery of drugs and nucleic acids.