Sadao Watanabe (渡辺 貞夫, Watanabe Sadao, born 1 February 1933) is a Japanese jazz musician who plays alto saxophone and sopranino saxophone. He is known for his bossa nova recordings, although his work encompasses many styles, with collaborations from musicians all over the world.

Watanabe was born on 1 February 1933 in Utsunomiya, Japan. His father, a professional musician, sang and played the biwa. Watanabe was attracted to jazz from an early age, in part due to the strong cultural influence stemming from the American post-war presence in Japan. He learned the clarinet while in high school after convincing his father over the course of six weeks to buy him a second-hand instrument.

In 1951, Watanabe moved to Tokyo and began playing the alto saxophone. He started studying the flute in 1953 with Ririko Hayashi from the Tokyo Philharmonic Orchestra. Watanabe joined Toshiko Akiyoshi‘s Cozy Quartet and began leading the group when Akiyoshi moved to the USA.^[1] By 1958, Watanabe had performed with leading musicians and quartets. In 1961, his first album as a leader, the self-titled Sadao Watanabe, was released.