Poly(vinyl alcohol)s (PVAs) are very popular dispersants for the construction of colloids and common shell-constituents of microcapsules but remain mostly unexplored as building blocks for the design of nanocapsules through nanoprecipitation or other processes. Herein, we first show that model commercial PVAs and oils can be concomitantly engaged in solvent-shifting procedures to give rise to oil-filled nanocapsules in one step. Next, we report the synthesis of precisely defined water-soluble glyco-PVAs by reversible addition-fragmentation chain transfer (RAFT) copolymerization of 6-O-vinyladipoyl-d-glucopyranose and vinyl chloroacetate and selective alcoholysis reactions. We finally demonstrate that these glycopolymers are excellent candidates for the straightforward conception of oil- and drug-filled, surface- and/or core-tagged, stealth, and degradable nanocapsules by nanoprecipitation.