The use of antibiotics as growth promotors or for the prevention of some poultry diseases has face global concern and serious criticism. Their addition to poultry feed show hazardous effects including development of antimicrobial resistance and the potential harmful effect on humans’ health. To eliminate these threats, there is increasing interest to search for natural alternatives. Plant derivatives such as garlic (Allium sativum L.) and its derivatives are nowadays extensively used in poultry production system. Dietary supplementation of broilers and layers with garlic induced improvement of production parameters, carcass quality, and intestinal integrity. Modulation of the immune response against important viral diseases and increasing the immune organs body weight ratio resulting from supplementation of poultry with garlic. Moreover, garlic showed modulation of gut health through the antibacterial and antiparasitic activities. Treatment with garlic also can mitigate the oxidative stress and reduce the free radicals production. Reduction of cholesterol level, but improvement of some liver and blood parameters were also reported following dietary inoculation of garlic. This review was designed to search on the impact of garlic as feed additives on performance, immunity, gut health, antioxidant status, and blood parameters of poultry.