A pharmaceutically and biologically relevant molecule, pyridoxine hydrochloride (vitamin B6), was encapsulated inside the cavityof a molecular container, cucurbit[7]uril (CB[7]), in aqueous solution. The CB[7] based “nanocapsule” of vitamin B6has beeninvestigated for the first time, via1H NMR and UV-visible spectroscopic titrations (including Job’s plot) andab initiomolecularmodeling. The results have demonstrated that vitamin B6forms stable host-guest complexes within CB[7] in 1 : 1 stoichiometry,with a binding affinity of(4.0±0.5)×103M−1. Such a nanocapsule could potentially find application in vitamin B6formulation forthe purpose of enhancing the stability, absorption, and delivery of this important vitamin.