Île du Lys, also known as Le Lys or Ile du Lise, is one of the Glorioso Islands, north-west of Madagascar. It is administered by France.
The island has a prominent sand hill and a saltwater lagoon. Trees on the island can grow up to 10 metres (33 ft) in height.
The island has been identified as an Important Bird Area (IBA) by BirdLife International because it supports a very large colony of about 100,000 pairs of sooty terns, as well as 100 pairs of brown noddies. There are no resident landbirds.
Coordinates: 11°31′03″S 047°22′23″E / 11.51750°S 47.37306°E