It is a large snake, reaching almost 2 m (6 1⁄2 ft) in total length.

Colours are greyish-brown with black crossbars that are most distinct interiorly.

It is a rear fanged venom snake but there are not known casualties registered.

It is found in India, Bangladesh, Myanmar, Cambodia, Thailand, Nepal, Malaysia, and Vietnam.

Boiga siamensis is an oviparous species, with sexually mature females laying eggs, 6–12 per clutch