The present study was conducted to investigate the efficacy of oral administration of L. reuteri on growth performance, intestine histomorphology, immunological and gut microbiome of broilers. A total of twenty healthy chickens were used in a five-week experimental trial. Birds were assigned into one of two groups with orally administrated L. reuteri probiotic and without probiotic-(Control -Phosphate-buffered saline). A significant (p<0.05) body weight gain was observed in the chickens in L. reuteri treatment group compare to those in the control group at the end of the trial. In addition, the serum IGF-1 cytokines level significantly enhanced in L. reuteri treatment group. However, there were no notable effects observed on the villus height, crypt depth, muscularis thickness, and submucosal thickness in chickens orally inject with and without L. reuteri. At the phylum level, the presence of Firmicutes (99.5%) was highly abundantin the L. reuteri treatment group. Moreover, the fecal microbial communities of Lactobacillus (99.9%) showed average relative abundance at genus level in L. reuteri treatment group. From this, we concluded that oral administration of L. reuteri would be beneficial to enhance the body weight gain, gut microbiome, and immune status of broiler.