Startup or start-up may refer to:
- Booting, an initialization period that computers and electronics go through when first turned on
- Project commissioning, the act of starting for the first time a technical installation
- Startup company, a recently formed company
- Start-Ups: Silicon Valley, a reality television series about startup companies that premiered in 2012
- startup, the title given in some countries to Antitrust (film)
- Startup.com, a 2001 documentary film about the dot-com start-up phenomenon
- Startup, Washington, a census-designated place in Snohomish County, Washington
- Sign-on, when broadcasters start transmissions on a day