This small owlet has a rounded head and is finely barred all over. There is no clear facial disk and the wings are brownish and the tail is narrowly barred in white. There are two subspecies, the nominate form is found in the plains of India and Sri Lanka, while G. r. malabaricum of the Western Ghats is shorter tailed and shows more brown on the head. It has been suggested that the latter may warrant full species status.
The plumage on the upper parts is dark black-brown barred with white. The wing coverts have white and rufous patches. The primaries and secondaries are dark brown and barred with pale chestnut. The lower side is whitish or pale rufous barred with black. There is a whitish patch on the chin, upper breast and centre of the abdomen. The iris is yellow, the bill and tarsi are greenish with black claws.
In Sri Lanka, the chestnut-backed owlet (Glaucidium castanonotum) was once included as a subspecies but this is elevated to full species. It is found in the wet zone ,whereas G. radiatum is found in drier forests.
They are found in habitats ranging from scrub forest to deciduous and moist deciduous forests. They are found south of the Himalayas and in some parts of the Himalayas up to an elevation of 2,000 m (6,600 ft), extending from Dalhousie in the west, east to Bhutan.
