Omachi Nishi-koen Station (大町西公園駅, Ōmachi Nishi-kōen-eki) is a subway station on the Sendai Subway Tōzai Line in Aoba-ku, Sendai, Japan, operated by the municipal subway operator Sendai City Transportation Bureau.

Omachi Nishi-koen Station is served by the 13.9 km (8.6 mi) Sendai Subway Tōzai Line between Yagiyama Zoological Park and Arai, and is located 5.0 km (3.1 mi) from the western terminus of the line at Yagiyama Zoological Park Station.

The station has one island platform serving two tracks on the second basement ("B2F") level.

The ticket barriers are located on the first basement ("B1F") level.

From fiscal 2018, this station will be staffed and operated by sub-contracted employees from the security company Alsok.