Lignocellulose is a core component of plant biomass and the most abundant carbohydrate polymer in nature. It is cheap and renewable and has several potential applications; however, it remains underutilized because of its recalcitrance to degradation. Cellulolytic microbes have been found in the gut of herbivorous insects, such as grasshoppers. This study aimed to isolate lignocellulolytic bacteria from the gut of grasshoppers (Oxya chinensis) and determine their diversity and potential biomass-degrading activity. A total of 27 culturable isolates were obtained from the grasshopper foregut, midgut, and hindgut. The bacteria hydrolyzed cellulose and lignin, as indicated by a cellulolytic index of 0.12–1.23 and ligninolytic index of 0.1–1.47. Five potential cellulolytic bacterial isolates were selected. Based on 16S rRNA sequencing, the isolates were identified as Bacillus wiedmannii (foregut), Bacillus marcorestinctum, Bacillus halotolerans (midgut), Paenibacillus zanthoxyli, and Bacillus hominis (hindgut). The highest specific cellulolytic activity (0.0068 U/mg) was detected in B. wiedmannii (OCF2), which could be exploited as a potential source of cellulases.