Jethou (/ʒɛˈtuː/zhe-TOO) is a small island that is part of the Bailiwick of Guernsey in the Channel Islands, located immediately south of Herm, with an area of around 44 acres (18 ha). It is privately leased, and not open to the public. The island has an area of approximately 44 acres (18 ha), and is inhabited, as of the 1996 census, by 3 people; there is only one house. Jethou is administered by the Bailiwick of Guernsey. The island is entirely administered by the States of Guernsey; but is currently owned by Peter Ogden, a founder of Computacenter.
On the top of the island, there is a marker. It is said that pirates used to be hanged on it in chains, as was done at nearby Crevichon. Jethou is also an area where Puffins can be found, in the east.