ID or its variants may refer to:
- İd or Narman, a town in Turkey
- Idaho, US (postal abbreviation ID)
- Indonesia, ISO 3166-1 alpha-2 country code "ID"
Periodicals
- I.D. (magazine), an American magazine focusing on Architecture, Graphic and Industrial Design
- i-D, a British fashion magazine
- Ideas and Discoveries (i.D.), a magazine covering science, with heavy interest in social science
- ID (public relations), a public relations firm
- ID Labs, an American music production and engineering team
- iD Mobile, a telephone network owned by Carphone Warehouse
- Interlink Airlines (IATA airline code ID), an airline based in Johannesburg, South Africa
- Batik Air (IATA airline code ID), an airline based in Jakarta, Indonesia
- Citroën ID, a variant of the Citroën DS car
- Volkswagen ID. series, a series of concept cars that have been promoted into production
- id Software, an American video game developer
- International dollar, common name for the Geary–Khamis dollar, a hypothetical unit of currency
- Invoice discounting, a form of Factoring (finance) in the UK
Design and engineering
- Industrial design, a process of designing products for mass production
- Information design, the practice of presenting information in a way that fosters understanding
- Inside diameter, also 'inner diameter' or 'I.D.'; a dimension commonly used to specify the size of tubing or pipe
- Interaction design, the practice of designing interactive digital products, environments, systems, and services
- Interior design, the art and science of enhancing the interior of a building
- Instructional design, the study of creating better instructional experiences
Psychology
- Id, one of the Id, ego and super-ego psychic apparatus defined in Sigmund Freud's structural model of the psyche