Shu Watanabe (渡辺 周, Watanabe Shū, born December 11, 1961) is a Japanese politician of the Constitutional Democratic Party of Japan, who serves as a member of the House of Representatives in the Diet of Japan (national legislature).

Watanabe is a native of Numazu, Shizuoka and graduated from Waseda University.

Watanabe was elected to the first of his two terms in the assembly of Shizuoka Prefecture in 1991 and then to the House of Representatives for the first time in 1996.

He served as the representative for the Shizuoka 6th constituency from 1996 to 2021, and again from 2024, and as the Tōkai proportional representation member from 2021 to 2024.

Watanabe is part of the CDP's shadow cabinet 'Next Cabinet' as the shadow Security Minister (replacement to the Minister of Defense).