PTO
- 75A-4 and KWS-1
- Body Love (album)
- P.T.O. (video game)
- Pacific Theatre of Operations (disambiguation)
- Paid time off
- Parent teacher organization
- Parietal-temporal-occipital
- Patent and Trademark Office (disambiguation)
- Peace Train Organisation
- Peeled tail-on shrimp
- Permission to officiate
- Phoenix Thunderbirds Open
- Please Turn Over
- Power take-off
- Professional Triathletes Organisation
- Promenade Theatre Orchestra
- Proof-theoretic ordinal
- Public Telecommunications Operator
- Public Transport Operator
- The Phantom of the Opera (adaptations)
- Zoʼé language