The lesser fish eagle is a medium-sized bird, measuring 50 to 70 cm in length and weighing 780 to 800 grams. The wingspan is 120 to 160 cm. It has greyish-brown plumage. The belly and thighs are white. The legs are cream-coloured with black talons. The eyes are light yellow. The head is small and the tail is rounded. Its call is a cackling sound.