Isabelle Yakovlevna Kremer (Russian: Изабелла Яковлевна Кремер; 21 October 1887 – 7 July 1956) was a soprano of Russian Jewish descent who at various times of her life held citizenship in Russia, the United States, and Argentina. She first drew notice as a teenager for her revolutionary poetry which was published in an Odessa newspaper. She began her professional singing career as an opera singer in Europe during the second decade of the 20th century. By the time of her relocation to the United States in 1924, she had abandoned her opera career in favor of performing as a concert soloist and recitalist.

As a recitalist Kremer not only sang works from the classical repertoire, but also performed folk music from a variety of countries and in many languages. She was possibly the first woman to perform Yiddish song on the concert stage. In 1927 she began performing as a vaudeville artist while continuing to perform extensively as a recitalist. In 1938, she moved to Argentina where she lived the last 18 years of her life. In 2000 her life was the subject of a television documentary entitled Isa Kremer: The People's Diva which was made for The Jewish Channel.