The Tōkyū Tamagawa Line 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. The operator's name, Tōkyū, is included in the formal name of this line.

The Tokyu Corporation a contraction of and formerly Tōkyō Kyūkō Dentetsu kabushiki gaisha until 2 September 2019, is a Japanese keiretsu or conglomerate headquartered in Shibuya, Tokyo. While a multinational corporation, its main operation is the Tokyu Railways Company, Ltd. , a wholly-owned subsidiary operating railways in the Greater Tokyo Area.