PTT may stand for:
- Postal Telegraph and Telephone (several)
- Postal Telephone and Telegraph (several)
- Public Telegraph and Telephone (several)
- Public Telephone and Telegraph (several)
- Ministry of Post, Telegraph and Telephone (Iran)
- Part task trainer (military)
- Partial Thromboplastin Time
- Partido Trabalhista Timorense
- Poste, Téléphone et Télécommunications (France)
- Protein Truncation Test
- Push to talk