Ethanolic extract of olive (Olea europaea) leaves contains phenolic compounds; oleuropein and ligstroside. The current study was designed to investigate the antibacterial property of Olea europaea leaf extract (OLE) (orally @10ml/l) alone and in combination with antibiotics in Salmonella gallinarum infected broiler chicks. A total of 125 one day old chicks were divided into 5 equal groups (25 chicks in each). Two groups were kept as negative and positive control, while others were supplemented with OLE, antibiotic, and OLE + antibiotic, respectively. On 14th day, experimental birds were infected with a field isolate of S. gallinarum (8.5×108 CFU/ml). The study revealed that morbidity and mortality rates were significantly lower in OLE supplemented groups. While there was a significant increase in body weight, erythrocytic count, hemoglobin concentration, and packed cell volume in OLE supplemented groups. Moreover, OLE was found with in-vitro zone of inhibition (18mm) against this bacterium. There was also a positive impact of OLE supplementation on total protein, albumin, and globulin concentrations than that of the rest of the groups. In conclusion, OLE has antimicrobial properties against S. gallinarum along with anabolic effect on the weight gain of broiler chickens and reduces the morbidity and mortality rate.