A 2 × 3 factorial arrangement of treatments was used to study the effects of acidified drinking water (ADW) as 0 or 350mL acidifier/1,000 L with 3 different wheat forms including ground wheat (GW), whole wheat (WW), or pelleted whole wheat (PWW) on growth performance, gizzard and proventriculus development, intestinal morphology, and microbial population of broiler chickens fed pelleted corn-soybean meal-based diets. GW, WW, and PWW were added at 50,100, and 150g/kg of the diet during starter (d 0 to 10), grower (d 10 to 24), and finisher (d 24 to 35) phases, respectively. A total of 300male broiler chickens at 1-d-old were randomly distributed into six treatments of five replicate pens each. During the starter and grower phases, GW inclusion tended to increase feed intake (P < 0.05), while WW improved feed conversion ratio (FCR) during all experimental phases (P < 0.05). Feed intake during the grower phase decreased and FCR during the starter and grower phases improved in broiler chickens, which received ADW (P < 0.05). An interaction between the wheat form and ADW were observed for the relative weight and muscular thickness of gizzard and pH of gizzard and proventriculus contents (P < 0.05). Inclusion of WW improved the relative weight, length, and width of gizzard and proventriculus and gizzard muscular thickness (P < 0.05). The gizzard weight increased in broiler chickens received ADW, while pH of gizzard contents decreased in those receiving ADW (P < 0.05). Feeding WW increased villus length (VL) and villus area (VA) compared to PWW inclusion, while the ratio of VL to crypt depth (CD) was the greatest in broilers fed WW (P < 0.05). An increase in VL, VA, or VL/CD was observed in broiler chickens, which received ADW (P < 0.05). In microbial population, ADW tended to increase Lactobacillus and decrease Escherichia coli populations (P < 0.05). Lactobacillus population increased in broiler chickens fed WW diet (P < 0.05). In conclusion, WW inclusion in combination with ADW was found to be a suitable promoting of growth performance, gizzard development, intestinal morphology, and microbial population in broiler chickens. All rights reserved, Elsevier.