This study evaluated the effects of Bacillus coagulans (B. coagulans) as an alternative to antibiotics on growth performance, antioxidant capacity, immunity function and gut health in broilers. A total of 480 one-day-old broilers were randomly divided into 3 treatments with 8 replicates comprising 20 broilers each. The experiment lasted 42 d. Treatments included: basal diet without antibiotics (NCO); basal diet supplemented with 75 mg/kg chlortetracycline (ANT); basal diet supplemented with 5 × 10 CFU/kg B. coagulans(BC). The B. coagulans enhanced body weight (BW) and average daily gain compared with the NCO group (P < 0.05). However, there were no significant differences in average daily feed intake and feed: gain ratio (F: G) among three groups (P > 0.05). The B. coagulans significantly increased catalase, superoxide dismutase, and glutathione peroxidase levels and reduced malondialdehyde levels (P < 0.05). The serum immunoglobulins (IgA, IgM, and IgY) were significantly higher in the BC group when compared to the NCO and ANT groups (P < 0.05). The B. coagulans also markedly reduced serum levels of proinflammatory factors (IL-1β, IL-6, and TNF-α) and enhanced anti-inflammatory factor (IL-10) concentrations compared with control group (P < 0.05). Moreover, compared with the control group, BC significantly inhibited serum xanthine oxidase activity (P < 0.05). The levels of acetic acid, propionic acid, butyrate, isobutyric acid and valerate in BC group were significantly increased on d 42 compared with the NCO and ANT groups (P < 0.05). Furthermore, BC significantly altered cecal microbiota by reducing Desulfovibrio and Parasutterella, and by increasing Alistipes and Odoribacter (P < 0.05, P < 0.05, P < 0.001, P < 0.01, respectively). In conclusion, dietary B. coagulans, when used as an alternative to antibiotics, improved body weight, average daily gain, antioxidant capacity, immunity function and gut health in broilers.