The incorporation of antimicrobials in poultry production systems has been linked with the development of resistant bacteria that spread to the environment, transmit to humans, and consequently induce a serious risk for public health. Therefore, searching for natural antibiotic alternatives could help in minimizing the harm to food safety, environmental contamination, and the overall health hazard. Phytobiotics are effectively used as antimicrobial feed additive alternatives worldwide. Many phytochemicals found in herbs, spices, plant extracts, and essential oils have demonstrated potential bioactivities, including antioxidant, antimicrobial, immunomodulatory, and anti-inflammatory properties. Tea is included in the list of phytogenic substances with numerous health benefits. Green tea (GT) (Camellia sinensis) has more than 200 bioactive compounds and 300 different substances, including polyphenols, alkaloids, volatile oils, amino acids, polysaccharides, lipids, vitamins, and minerals. In poultry production, the dietary GT and its derivatives (extract, leaves, by-products, polyphenols, and flowers) are supplemented for improving performance, immunity, and blood parameters; alleviating stressors and reducing microbial infections. Therefore, this article was designed to investigate the different influences of using GT as a feed additive in the poultry production system regarding its effects on the production performance of broilers and layers, carcass characteristics, oxidative stressors, blood parameters, immunity, and microbial balance.