The diffusion and sorption of water, methanol, and methyl acetate in 88% hydrolyzed polyvinyl alcohol were studied using gravimetric sorption. The thermodynamic data obtained were analyzed using the Flory-Huggins theory and the Flory-Rehner model, which accounts for the cross-linking caused by the semi-crystalline nature of the polymer. The diffusion data are compared with those obtained with the 99% PVOH and correlated with the Vrentas-Duda free-volume theory. While the correlation is good for methanol and methyl acetate, a deviation is observed for water at the high concentrations. The possible causes of such a deviation are discussed.