We present a postfunctionalization strategy to formulate noncationic RNA-polymer complexes for RNA delivery. Utilizing the methylated pyridinium moieties on the polymer, RNA-polymer polyelectrolytes were first formed via electrostatic interaction. Next, the polyelectrolytes were partially cross-linked with dithiothreitol, "locking" the RNA inside the complex and leaving the rest of the N-methylated pyridyl disulfide groups to subsequently react with thiols. We carried out the postfunctionalization using thiolated oligoethylene glycol and removed a majority of the cationic moieties among the RNA-polymer complexes. The strategy facilitates the noncationic RNA-polymer complexes with tunable RNA-release rates in the presence of intracellularly abundant glutathione. With significantly reduced cytotoxicity, the resultant complexes protect RNA against the enzymatic degradation by ribonuclease A and fetal bovine serum. Moreover, the RNA-polymer complexes demonstrated successful siRNA delivery and gene specific knockdown in HeLa cells.