Eighty crossbred pigs were used in a factorial design experiment to determine the effects of micronization and β-glucanase supplementation on the performance of growing-finishing pigs fed diets based on hulless barley. Micronization increased the percentage of gelatinized starch in the diets while enzyme supplementation decreased diet viscosity. Enzyme supplementation increased the digestibility coefficients for dry matter, crude protein and gross energy while micronization had no effect. Micronization also had no effect on pig growth rate. However, feed intake was slightly reduced resulting in a significant improvement in feed conversion. Enzyme supplementation had no effect on growth rate but produced a significant improvement in feed conversion during the finishing period. Neither enzyme supplementation nor micronization had any effect on carcass traits.