An experiment was conducted to investigate the effect of oolong tea (Camellia sinensis) pow-der (OTP) particle size on growth performance, fat deposition, meat quality and antioxidantactivity of ducks. A total of 252 Cherry Valley meat ducks (16 days old) with similar ini-tial body weight (744 ± 6 g) were selected and randomly divided into three groups withsix replicates of fourteen ducks (seven males and seven females) each and fed a controldiet or one of two test diets supplemented with 1% OTP with two different mean particlesizes categorised as coarse (357 m) and fine (16 m) until 42 days of age. Treatments didnot affect growth performance of ducks. Abdominal fat yield, subcutaneous fat thickness,intramuscular fat width and serum triglyceride (TG) concentration were reduced (P < 0.05)by fine but not coarse OTP. Both forms of OTP decreased (P < 0.05) drip loss of pectoralismajor muscle, but only fine OTP increased (P < 0.05) superoxide dismutase (SOD) activ-ity and decreased (P < 0.05) malondialdehyde (MDA) content in serum. In conclusion, fineOTP would be more effective in decreasing fat deposition and improving meat quality andantioxidant activity in meat duck.