The knowledge of bacterial communities in the brackish shrimp farming in Vietnam is still insufficient. Here, the diversity of gut bacteria and nearby environment in asymptomatic and symptomatic black tiger shrimp farms in Bac Lieu province, Vietnam was examined by 16S rRNA Illumina sequencing. The dominant bacterial phyla were Proteobacteria, Bacteroidetes, Cyanobacteria, Crenarchaeota and Actinobacteria. Principal coordinate analysis showed bacterial communities in the gut and rearing-water of asymptomatic shrimps were separated, while those of symptomatic shrimps and rearing water were clustered together. These findings provide valuable information on the microbial community and contribute to control the diseases in shrimp farms.