The Tōkyū Tamagawa Line (東急多摩川線, Tōkyū Tamagawa-sen) is a commuter railway line in Japan owned by private railway operator Tokyu Corporation.

It runs between Tamagawa and Kamata in southwest Tokyo, entirely within Ōta ward.

All the rolling stock is shared with Tokyu Ikegami Line.

This would provide an interchange between the lines, improving accessibility to Tokyo's Haneda Airport ahead of the 2020 Summer Olympics.

As of June 2022[update], Ōta Ward has agreed with the Tokyo Metropolitan Government to pay 70% of the project cost of ¥136 billion (2021) (US$1.24 billion) while having the city government responsible for the remaining 30%.