| Nishi-Ōi Station | |
| Style: | JR East |
| Native Name: | 西大井駅 |
| Native Name Lang: | ja |
| Address: | 1 Nishi-Ōi, Shinagawa-ku, Tokyo |
| Country: | Japan |
| Coordinates: | 35.6019°N 139.7218°W |
| Operator: | JR East |
| Platforms: | 2 side platforms |
| Tracks: | 2 |
| Connections: | Bus terminal |
| Structure: | Elevated |
| Code: | JO-16, JS-16 |
| Opened: | 2 April 1986 |
| Map Type: | Japan Tokyo#Japan |
| Map Dot Label: | Nishi-Oi Station |
is a railway station on the Yokosuka Line in Shinagawa, Tokyo, Japan, operated by East Japan Railway Company (JR East).
The station is composed of two elevated side platforms and two tracks, and is located below the tracks of the Tōkaidō Shinkansen.
There is a fork connecting to the Yamanote Line on the south side of the station.
The line coming from Yokohama splits at this station to the Yokosuka Line toward Shinagawa Station and the Shōnan-Shinjuku Line toward Ōsaki Station.
The station opened on April 2, 1986. With the privatization of Japanese National Railways (JNR) on April 1, 1987, the station came under the control of JR East.
Shonan-Shinjuku Line services began operating on December 1, 2001.