The fez (Turkish: fes, Ottoman Turkish: فس, romanized: fes), also called tarboosh/tarboush (Arabic: طربوش, romanized: ṭarbūš, derived from Persian: سرپوش, romanized: sarpuš, lit. 'cap'), is a felt headdress in the shape of a short cylindrical, truncated (peakless) hat, usually red, and sometimes with a black tassel attached to the top. The name "fez" refers to the Moroccan city of Fez, where the dye to color the hat was extracted from crimson berries. However, its origins are disputed.

The modern fez owes much of its popularity to the Ottoman era. The fez became a symbol of the Ottoman Empire in the early 19th century. In 1827, Mahmud II mandated the fez as a modern headdress for his new army, the Asakir-i Mansure-i Muhammediye. The decision was inspired by the Ottoman naval command, who had previously returned from the Maghreb having embraced the style. In 1829, Mahmud issued new regulations mandating use of the fez by all civil and religious officials. The intention was to replace the turban, which acted as a marker of identity and so divided rather than unified the population. The fez was subsequently outlawed in Turkey in 1925 as part of Atatürk's reforms.

The fez has been used as part of soldiers' uniforms in many armies and wars for centuries, including the Bahawalpur Regiment in Pakistan as late as the 1960s.

It is still worn in parts of South Asia, the Middle East, North Africa, and in Cape Town, South Africa. It has also been adopted by various fraternal orders.