This study was conducted to examine the effect of green tea on body, adipose tissue, and liver weights and adipose tissue weight to body weight ratio and the adipogenic differentiation and expression of adipogenic transcripts in chicken (Gallus gallus) preadipocytes. In experiment one, chicks were weighed and randomly assigned to a control diet (CTRL) and green tea treatment (GT 1%, w/w) for 38 days. In experiment 2, preadipocytes were isolated from 20 wk old chicken and treated with an adipogenic cocktail (DMIOA) containing 500 nM dexamethasone, 0.5 mM 3-isobutyl-1-methylxanthine, 20 µg/mL insulin, and 300 μM OA, DMIOA+30 µg of extract B, E, H, Mc, T, and W, respectively, for 48 h. Data were analysed using the General Liner Model procedure of the Statistics Analysis System (SAS) Institute version 9.4, and differences were considered significant at P < 0.05. Gene expression was measured using quantitative real-time PCR. GT 1% significantly reduced body (-9%; P = 0.0447), liver (-20%; P = 0.0206), and abdominal fat weight (-44%; P = 0.0055) compared with the control (CTRL) group (GT 0%). The abdominal fat/body weight ratio of green tea supplemented group (-36%; P = 0.0125) was also significantly lower than that of control group. In cell culture study, all green tea extracts inhibited C/EBPα and β mRNA expression compared to DMIOA. DMIOA+B, T, or W reduced mRNA expression of FABP4 by three-fold compared to DMIOA. Although all green tea extracts reduced adipocyte formation, T and W had the strongest anti-adipogenic effects. These results demonstrate that supplementation of green tea could be an effective strategy in the control of obesity in chickens.