The present work was designed to evaluate the effect of garlic (Allium sativum) as a natural feed ingredient on growth performance and immune response in Nile tilapia (Oreochromis niloticus). A total of 150 juvenile’s tilapia were taken randomly and divided into five experimental units (10 fishes per unit) with three replicates. Fish was hand feeded containing five different levels of garlic (T1, control) 2.5 (T2), 5.0 (T3), 7.5 (T4), and 10g/500g (T5) in powdered form. Fish were fed at 6% of body weight twice, daily. Feed utilization was estimated in terms of feed conversion ratio (FCR). The growth was measured in terms of total weight gain (TWG) and length of the body was calculated. At the end of the trial, immune response monitored in terms of hemoglobin (Hb), hematocrit (Ht), white blood cells (WBC), red blood cells (RBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC). Average mean weight gain (11.03±0.8g) and average mean length (7.8±0.4cm) was observed maximum in T4 as compared to other dietary treatments. There observed a significant difference (P<0.05) in FCR among all the dietary treatments with highest in T4 (0.59±0.32). Dietary treatment T5 (10/500g) showed significance difference (P<0.05) in red blood cells (RBC) count (2.82±0.33), white blood cells (WBC) count (6.56±0.83), hemoglobin (24.89±2.67) and hematocrit (37.27±3.83) as compared to other treatment groups including control. The results of our study showed that dietary treatment T4 (7.5g/500g) showed maximum growth and FCR while dietary treatment T5 (10/500g) showed better immune response in tilapia over other dietary treatments. So, it is concluded that garlic can be used as immunity stimulant and to enhance growth performance in Nile tilapia.