The adult tree has a rounded crown, and commonly measures 7–12 metres (20–40 ft) tall, however in exceptional circumstances M. azedarach can attain a height of 45 metres (150 ft).
The leaves are up to 50 centimetres (20 in) long, alternate, long-petioled, two or three times compound (odd-pinnate); the leaflets are dark green above and lighter green below, with serrate margins.
The flowers are small and fragrant, with five pale purple or lilac petals, growing in clusters.
The fruit is a drupe, marble-sized, light yellow at maturity, hanging on the tree all winter, and gradually becoming wrinkled and almost white.