PDT may refer to:
Computers:
- PHP Development Tools, an IDE plugin for the Eclipse platform
- Portable data terminal, an electronic device that is used to enter or retrieve data via wireless transmission
Medicine:
- Patient-delivered therapy
- Photodynamic therapy, treatment for cancer and wet age-related macular degeneration, involving three key components, a photosensitizer, light, and tissue oxygen
- Population doubling time, a number indicating cell growth in cell cultures
- Pancreaticoduodenal transplantation
Other:
- Pacific Daylight Time (UTC-7), daylight saving time in western North America
- Paramount Domestic Television, US TV series distributor, now CBS Television Distribution
- Partido Democrático Trabalhista (Democratic Labour Party), a populist, social-democratic political party of Brazil
- Phi Delta Theta, an international fraternity
- Piedmont Airlines (ICAO airline code), an American regional airline operating for US Airways Express
- Plautdietsch (ISO 639-3 language code), a Low Prussian variety of East Low German, with Dutch influence
- Potentially Dangerous Taxpayer, an American taxpayer that has demonstrated a capacity for violence against the IRS
- Prague Dependency Treebank, a subset of the Czech National Corpus annotated along the lines of Functional Generative Description
- Eastern Oregon Regional Airport (IATA airport code), near Pendleton, Oregon
- Pattern day trader (also Pattern day trading, PDT violation), a stock trader who frequently buys and sells a security within the same trading day
- Peter Dengate Thrush, New Zealand barrister