| Olba Aqueduct | |
| Native Name: | Olba Su kemeri |
| Native Name Lang: | Turkish |
| Location: | Olba (ancient city) |
| Location City: | Mersin |
| Location Country: | Turkey |
| Coordinates: | 36.5861°N 33.9689°W |
| Building Type: | Aqueduct |
| Architectural Style: | Ancient |
| Material: | Granite |
| Opened Date: | 199 |
| Owner: | Turkish Republic |
Olba Aqueduct is a ruined Roman aqueduct in Mersin Province, southern Turkey.
The aqueduct is in Silifke ilçe (district) of Mersin Province at 36.5861°N 33.9689°W. It is about east of the sacred place of Diokaesareia (now called Uzuncaburç town) and close to the capital of Olba Kingdom (a local kingdom).
The aqueduct was commissioned by the Roman emperor Septimius Severus (193–211) in 199. On the inscription it reads "the city of Olba residents". The aqueduct underwent repairs during the reign of Byzantine emperor Justinian I (527–565) in 566.
The aqueduct is mostly demolished. A part of it can be seen to the west of the agora ruins. It is a double tier aqueduct. Its height is and its length over a valley next to the city is . There are observation towers around the aqueduct.[1] The source of the watercourse is Limonlu River also known as Lamas River around the village of Kızılgeçit[2] which is about to the northeast.