The aim of this study was to determine the effects of curcumin on meat quality and antioxidant profile of breast muscle in broilers. In experiment 1, birds were fed basal diet with an additional 0, 50, 100, or 200 mg/kg curcumin, respectively. The results showed that dietary curcumin significantly increased the redness values of meat, catalase activity, and ABTS radical scavenging activity and decreased drip loss at 48 h. In experiment 2, birds reared under heat stress were assigned to similar treatments as experiment 1. Significant differences in the redox status of breast muscle were observed between the control and heat stress groups. The various levels of curcumin significantly prevented reactive oxygen species overproduction, enhanced the antioxidant defense system, and alleviated the abnormal change of antioxidant-related gene expression of muscle in heat-stressed birds. It was concluded that curcumin, as a potential antioxidant, improved meat quality and oxidant stability of muscle in broilers, whereas the inclusion of 50 and 100 mg/kg would be more efficient.