This study aimed to investigate the effect of the colour of monochromic light-emitting diode (LED) lighting on growth performance, tonic immobility duration, gait score, and hormone concentration in broilers. A total of 540 one-day-old broilers were randomly assigned into three lighting treatments: 1) 517-623 nm, 6500 K (white, WL), 2) 440 -480 nm (blue, BL), and 3) 503-540 nm (green, GL) LED light. Body weight and feed intake were recorded, weekly. The duration of tonic immobility and the gait score of the broilers were determined at d 28 and 35. Concentrations of growth hormone (GH), adrenocorticotropic hormone (ACTH) and insulin-like growth factor (IGF-1) were assayed on d 1, 7, 21 and 42. From d 14 to 42 broilers of the BL and GL groups were heavier than of the WL group. Although, there was no effect of lighting treatment on feed intake from d 0 to 21, GL and BL broilers consumed more feed than WL broilers from d 22 to 42. The duration of tonic immobility was not influenced by the LED light colour. Sex had a significant effect on tonic immobility duration. It was shorter in males than in females. There was no difference among groups in gait score at d 28. However, a better walking ability was obtained under GL on d 35. The WL broilers had the highest IGF-1 concentration on d 7. On d 42, birds under BL and GL lighting had lower ACTH concentration than under WL. The present results suggested that BL and GL improved body weight and reduced stress response of broilers. Furthermore, walking ability of broilers can be improved by GL lighting.