Fetlar is one of the North Isles of Shetland, Scotland, with a population of 86 at the time of the 2001 census. Its main settlement is Houbie on the south coast, home to the Fetlar Interpretive Centre. Fetlar is the fourth largest island of Shetland and has an area of sixteen square miles.

One of the strange features of Fetlar is a huge wall that goes across the island known as the Funzie Girt or Finnigirt Dyke. It is thought to date from the Mesolithic period. So sharp was the division between the two halves of the island, that the Norse talked of East and West Isle separately. One posited etymology is from fetill, meaning a "strap", so possibly the island's name means "two islands strapped together". It was recorded as "Fötilør" in 1490.

Another attraction on the island is the Gothic Brough Lodge, built by Arthur Nicolson in about 1820, and which is undergoing restoration by the Brough Lodge Trust. The Fetlar sheepdog trials take place annually, normally in July. The Fetlar Foy is very popular with Shetlanders and tourists alike. It takes place at midsummer on the Links at Tresta where folk are entertained with music, food and drink.