Wingspan c. 12mm.
Very similar to Case-bearing Clothes MothTinea pellionella, there has been some confusion in the past, and a substantial number of the previous records of that species were in fact found to be T. dubiella.
The larva feeds on a range of products, including woollen clothing and dried vegetable products, forming a portable case made from fibrous material. It can be found indoors, and often in birds' nests, but like many Tineidae, is becoming less common.
The species is fairly widespread over the British Isles. Adults are on the wing any time from May to September.