Dissolution of polymers is important in various areas, including microlithography, controlled drug and herbicide/fertilizer delivery, and recycling. The dissolution rates of an oxetane polymer in ethyl acetate were obtained and well correlated with a quasi-stationary dissolution model. Equilibrium solubility values obtained from the mathematical model on the basis of the best fit to the dissolution data were found to be in good agreement with equilibrium solubilities obtained in independent experiments. Mass transfer coefficients were also obtained from the mathematical model on the basis of the best fit, and the calculated activation energies were typical for diffusion controlled dissolution. The dissolution of highly filled polymers in various solvents was also investigated using the oxetane polymer filled with ammonium sulfate and aluminum fillers. The dissolution rates for the highly filled polymer were well correlated with a pseudo-homogenous diffusion model.