The red-tailed racer inhabits primary and mature secondary forest. It is mainly arboreal and is a renowned raider of birds nests: as a consequence it is often mobbed by birds when searching amongst trees for active nests. It also feeds on bats, rodents and lizards.

The body is thick-set, and the head wider than the body. The snout is long. Its scales are generally smooth, but sometimes may be vaguely keeled. The tongue is blue.

Dorsally it is a striking green colour, which is paler ventrally. The top of the head is darker green, and there is a vague dark stripe running through the eye. The tail is orange-red. Other less common colour forms occur, including variants which are blue-green, grey, orange or yellow-coloured throughout.

The red-tailed racer is wide ranging, and occurs from Burma and adjacent island groups through Thailand and Indochina to Peninsular Malaysia, Singapore, the Philippines, Sumatra, Borneo, Java and Lombok.