Deputy is a rank or title, or part of a title, used in various organizations with a codified command structure. It often designates someone who is "second-in-command," and as such, may precede the name of the rank directly above it. For example, a "Deputy Master" is likely to be second-in-command to the "Master" in an organization utilizing both such ranks. Dep. is the common abbreviation of "Deputy" and most widely accepted.

Deputy is also a last name, although not too common. It is thought to originate as a name in the 1400s in England.

Deputy may also refer to:

• An individual responsible for managing the finances and assets of another person in the UK
• Steward (office)
• Deputy (legislator), a legislator in many countries, including:
• A member of a Chamber of Deputies
• A member of a National Assembly
• A member of the Dáil Éireann
• A member of the States of Guernsey or the States of Jersey elected by a parish or district
• A subordinate
• Deputy sheriff, deputized by a sheriff to perform the same duties as the sheriff
• Deputy Director of the Central Intelligence Agency
• Deputy White House Chief of Staff
• Deputy Dawg
• Deputy, Indiana, a small town in the United States