Thessaloniki Urban Transport Organization
| Founded | 6 August 1957 |
|---|---|
| Headquarters | Al. Papanastasiou 90, 54644Thessaloniki, Greece |
| Service area | Thessaloniki metropolitan area |
| Service type | Bus transport network |
| Alliance | KTEL Thessalonikis, KTEL Serres, KTEL Chalkidikis |
| Routes | 267 (2 night routes) |
| Hubs | 2 |
| Stations | 5 |
| Fleet | 360 vehicles |
| Fuel type | Diesel |
| Operator | Greek Government |
| President | Taggiris Kostas |
| Website | www |
The Thessaloniki Urban Transport Organisation (Greek: Οργανισμός Αστικών Συγκοινωνιών Θεσσαλονίκης, romanized: Organismós Astikṓn Sygkoinōniṓn Thessaloníkīs), abbreviated OASTH (Greek: ΟΑΣΘ), is a mass transport company operating in Thessaloniki, Greece.
It was founded in 1957 and now covers a large area of the metropolitan area of Thessaloniki, the country's second-largest city. OASTH only includes bus transportation due to lack of other means of transport.