Sophie Adele Wyss (5 July 1897 – 25 December 1983) was a Swiss soprano who made her career as a concert singer and broadcaster in the UK. She was noted for her performances of French works, many of them new to Britain, for giving the world premieres of Benjamin Britten's orchestral song cycles Our Hunting Fathers (1936) and Les Illuminations (1940), and for encouraging other composers to set English and French texts. Among those who wrote for her were Lennox Berkeley, Arnold Cooke, Roberto Gerhard, Elizabeth Maconchy, Peter Racine Fricker, Alan Rawsthorne and Mátyás Seiber.
Wyss was born to a musical family in La Neuveville, Canton of Bern, Switzerland. Her two sisters, Emilie Perret-Wyss and Colette Feschotte-Wyss, were also singers, and the three sometimes performed together. She studied at the Geneva Conservatoire and the Basle Music Academy. In 1925 she married a British army officer, Captain Arnold Gyde, who after retirement from the armed forces became a publisher in London. He also became the treasurer of the Committee for the Promotion of New Music, founded in 1943.
Making her home in England, Wyss embarked on a career as a soloist. At first she failed to impress the critics. After an early recital in London in 1927, The Times said, "Miss Wyss has some pleasant notes in her voice, but the tone was tight in the upper range. A pronounced wobble, which appeared now and then, and a tendency to go out of tune showed that she has not yet gained sufficient control over her voice." By the 1930s her notices had improved from reserved to enthusiastic. The Times said that Wyss "possesses a soprano voice of an exquisitely yielding quality … a singer so completely satisfying that we would not trust ourselves to say how much of the pleasure we derived from her performances was due to her or the music itself."