PTT may refer to:
Businesses and organizations PTT Public Company Limited, a Thai oil and gas company Pashtun Tahafuz Tehrik, a human rights movement in Pakistan Pennsylvania Tunnel and Terminal Railroad, the New York Penn Station tunnel owner Pizza Time Theatre (now Chuck E. Cheese's), an American entertainment restaurant chain Police Tactical Team, Singapore Postal, telegraph and telephone service, a type of government agency Posterijen, Telegrafie en Telefonie (Netherlands) Postes, télégraphes et téléphones (France) PTT (Switzerland) Posta Telgraf Teşkilatı (Turkey) Prince's Trust Team, a British charitable youth programme
Music "PTT (Paint the Town)", a 2021 single by Loona Pull Tiger Tail, a British indie band (2006–2009)
Science Partial thromboplastin time, a coagulation measure Photothermal Therapy, a treatment Photothermal time, in plants 2β-propanoyl-3β-(4-tolyl)-tropane, a cocaine analogue Polytrimethylene terephthalate, a polyester Pulse Transit Time, a blood pressure measure
Technology PTT Bulletin Board System, a Taiwanese forum Pneumatic tube Push to talk (or "Press-to-Transmit"), in telecommunications Pass-the-ticket, in hacking
Other uses Petronas Twin Towers, Kuala Lumpur, Malaysia Port Talbot Town F.C., a Welsh association football club Power transition theory, an international relations theory