OTP

Arts, entertainment, and media

• One true pairing, a term used in media fandom

Businesses and organizations

• OTP Bank, (Országos Takarékpénztár és Kereskedelmi Bank Nyrt), a commercial bank in Hungary
• Office of Telecommunications Policy, in the United States White House, between 1970 and 1978
• Old Town Pizza, award-winning company with stores in Auburn & Lincoln, CA, USA

Judaism and Christianity

• Old Testament Pseudepigrapha

Sports

• Oulun Työväen Palloilijat, association football club from Finland

Technology

• One-time pad, in cryptography
• One-time password, a password that is valid for only one login session or transaction
• One-time programmable, a type of programmable read-only memory in electronics
• Open Telecom Platform, a distribution of Erlang programming language and a collection of middleware
• Opposite Track Path, in optical DVD technology

Transportation

• OTP, the IATA code for Henri Coandă International Airport in Bucharest, Romania
• On-time performance, the level of success of the service (such as a bus or train) remaining on the published schedule

Other uses

• Outside the Perimeter, used by residents of Metro Atlanta to refer to suburban areas outside of the Interstate 285 beltway