A warden is a custodian, defender, or guardian. Warden is often used in the sense of a watchman or guardian, as in a prison warden. It can also refer to a chief or head official, as in the Warden of the Mint.

Warden is etymologically identical to guardian, both terms deriving from the Old French garder which in turn is of Germanic origin, wartēn meaning to watch or protect.

Types of wardens include:

• Prison warden, the chief administrative official of a prison
• Warden (college), head of some university colleges and academic institutions in the United Kingdom and Australia
• Warden of the Mint, historical highest-ranking officer of the Royal Mint of the United Kingdom
• Warden, rank of seniority within a City of London livery company
• Churchwarden, a lay officer in an Anglican or Episcopal church
• Fire warden, a person designated to aid firefighters at a building or community level
• Game warden, an officer empowered to enforce the hunting and trapping laws of a jurisdiction
• Mining warden, presiding officer in a warden's court
• ARP Warden, responsible for enforcing Air Raid Precautions in the United Kingdom during World War II air raids
• Warden, the chief royal official of a royal forest
• Street warden, an officer aiding police at a community level
• Warden, an officer in a Knights of Columbus council
• Warden, a rank of Masonic lodge officer
• County warden, the head of county governments in Ontario and Nova Scotia, Canada, similar to mayors in cities
• Resident assistant, may be referred to as a warden at some educational institutions
• Park ranger, also called a park warden or forest ranger, a person entrusted with protecting and preserving parklands
• Parking enforcement officer, also called a traffic warden or parking inspector, an officer who issues tickets for parking violations
• Sheltered housing officers, referred to formerly (and still by some) as "wardens"
• Wardens of the Coast
  • Lord Warden of the Cinque Ports, a ceremonial office of the Confederation of Cinque Ports of the southeast coast of England
  • Lord Warden of the Marches, a historical office in Scotland and England
• Lord Warden of the Stannaries, a historical office in Cornwall
• Warden of the Swans, an office in the Royal Household of the Sovereign of the United Kingdom, created in 1993