Qaid (Arabic: قائد qāʾid, "commander"; pl. quwwād), also spelled kaid or caïd, is a word meaning "master" or "leader." It was a title in the Norman kingdom of Sicily, applied to palatine officials and members of the curia, usually to those who were Muslims or converts from Islam. The word entered the Latin language as Latin: gaitus or Latin: gaytus. Later the word was used in North Africa for the governor of a fortress or the warden of a prison, also in Spain and Portugal in the form with the definite article "alcayde" (Spanish) "alcaide" (Portuguese). It is also used as a male Muslim given name. It furthermore is a designation for leaders of bands of gangsters.
- Thomas Brun (active 1137-1154), Englishman who served Roger II of Sicily
- Ahmed es-Sikeli, known as Caid Peter (active 1160s), eunuch in the court of Sicily, confidant of Margaret of Navarre
- Caïd Richard (died 1187) Great Chamberlain under William I of Sicily and Margaret of Navarre
- Murat Reis the younger 17th Century Dutch renegado appointed Caid over the region including the kasbah of El-Oualidia, the port of Saffia, and Maladia (Muladie) by the Sultan of Morocco
- Sir Harry MacLean (1848–1920), Scottish soldier, and instructor to the Moroccan Army
- Quaid-e-Azam, meaning great leader, title of Muhammad Ali Jinnah (1876–1948), founder of Pakistan
- Grands caids, Berber feudal rulers of southern quarter of Morocco under the French Protectorate
People with the given name
- Qaid ibn Hammad (1028–1045), ruler of Algeria
- Kaid, nickname of Andrew Belton, (1882—1970), British Army officer active in Morocco
- Kaïd Ahmed (1921-1978), Algerian nationalist and politician
- Béji Caïd Essebsi (born 1926), Tunisian lawyer and politician
- Kaid Mohamed (born 1984), Welsh footballer
Alcaide as surname
- Anselmo Pardo Alcaide (1913-1977), Spanish entomologist.
- Chris Alcaide (1922–2004) American actor
- Carmen Alcayde (born 1973), Spanish TV presenter and actress
- David Alcaide (born 1978), Spanish pool player
- Guillermo Alcaide (born 1986), Spanish tennis player
- Ana Alcaide (born 1976), Spanish musician
- Draâ El-Kaïd, town in Algeria
- Alkaid or Elkeid, traditional name of Arabic origin for star Eta Ursae Majoris
- USS Alkaid (AK-114), U.S. Navy ship, named after the star
- Qaid (film), 1975 Hindi film starring Leena Chandavarkar and Kamini Kaushal
- Umar Qaid, 1975 Hindi Bollywood action film
- The Kingdom of Caid, Society for Creative Anachronism, encompasses Southern California, the Las Vegas metropolitan area, and Hawaii.
- Khuddamul Ahmadiyya chapter leaders are called Qaid. The Qaid in this terminology is a Muslim youth leader who guides his local khuddam in services to faith and nation.