OPT or Opt may refer for:
Computing /opt, a directory in the Filesystem Hierarchy Standard Option key, a modifier key on Apple keyboards OPT, the theoretically optimal page replacement algorithm, a page replacement algorithm for swapping out pages from memory
Other uses Occupied Palestinian Territories, an alternative name for the State of Palestine Ocean Power Technologies, a US owned renewable energy company Office des postes et télécommunications, especially in French Polynesia (Office des postes et télécommunications de Polynésie française) and in New Caledonia Operation Prime Time, a consortium of TV Stations to provide alternative prime time programming Optical projection tomography, a form of tomographic tissue imaging used in biomedical research Optional Practical Training, a period during which university students with an F-1 are permitted by the United States Citizenship and Immigration Services (USCIS) to work for one year on a student visa Optimized Production Technology, a production planning system created by Eliyahu M. Goldratt Outdoor Payment Terminal, a name sometimes used for the self-service user interface hardware at fuel stations Oral pressure therapy, a treatment for obstructive sleep apnea Overseas Passenger Terminal, Sydney Obshchestvennoye Rossiyskoye Televideniye (, ОРТ in Cyrillic script), the former name of Channel One Russia, a public broadcaster in Russia Oxford Placement Test Onboard Performance Tool, aviation device for landing calculations based on weather and runway conditions
See also Opt-out, to avoid receiving unsolicited product or service information Opting out, a political expression in Canada, describing the intention of a province to remove itself from a program administered by the federal government Opt in email, the option to receive bulk e-mail ORT (disambiguation), an acronym in Russian and Greek which appears like OPT