Sidney Lambert (c. 1838–1905) was an African-American pianist, music educator and composer, born before the American Civil War as a free person of color.
He and his family were noted for talent in music and gained international acclaim.
He and his older brother Charles Lucien Lambert studied music with their father.
Sidney Lambert also lived and worked in France, and served as a pianist in Portugal at the Royal court of King Dom Pedro, along with his nephew Lucien-Léon Guillaume Lambert, where he was recognized for innovation in music in the 1870s.
His papers are housed in the Bibliothèque Nationale de Paris, including thirty-two works dated 1866 to 1899.