PTA
- 1,3,5-Triaza-7-phosphaadamantane
- Andalusia Technology Park
- Pakistan Telecommunication Authority
- Parent–teacher association
- Passenger transport authority
- Paul Thomas Anderson
- Percutaneous transluminal angioplasty
- Peritonsillar abscess
- Persistent truncus arteriosus
- Pharmacy technical assistant
- Phosphate acetyltransferase
- Phosphotungstic acid
- Physical therapist assistant
- Pietà, Malta
- Planes, Trains and Automobiles
- Plasma thromboplastin antecedent
- Pohakuloa Training Area
- Point of total assumption
- Port Talbot Parkway railway station
- Post-traumatic amnesia
- Preferential trading area
- Pretoria
- Prevention of Terrorism Act (disambiguation)
- Program test authority
- Ptah (disambiguation)
- Public Transport Authority (Denmark)
- Public Transport Authority (Western Australia)
- Pulsar timing array
- Pure tone audiometry
- Purified terephthalic acid
- Spanish peseta