A feeding study was conducted to compare the effects of litter material, dietary fibre and sex on growth performance, organ development, mucosal morphometry and gut microbial communities in broilers. Seven hundred twenty day old Cobb chicks were allocated to 24 floor pens in a 2 x 2 x 2 factorial design with 3 pens of 30 birds per replicate (3 pens of males and 3 pens of females). Factors were: litter material, paper or hardwood shavings; dietary fibre, low or high and sex. Diets consisted of wheat, soybean meal, meat meal, expeller canola meal, poultry fat, vitamin and minerals. Birds and feed were weighed on days 7, 21, and 35. Low fibre groups contained no oat hulls whereas high fibre groups contained 70 g/kg oat hulls. Birds grown on hardwood shavings had larger gizzards (P < 0.01) and a more favorable FCR (P < 0.03) than those grown on paper litter at 35 d. Dietary oat fibre was more beneficial in birds reared on paper litter than hardwood shavings as evidenced by significant fibre by litter interactions at 35 d for FCR (P < 0.02) and caecal 'C. perfringens' counts (P < 0.01). Dietary oat fibre improved body weight at 7 d (P < 0.04), and lowered gizzard pH (P < 0.02) at 35 d. The results suggest that the combination of clean paper litter with high oat fibre diet may be beneficial in enhancing gut health in broilers.