Marie Jaëll (17 August 1846 – 4 February 1925) was a French pianist, composer, and music teacher.

She was born Marie Trautmann in Steinseltz, Bas-Rhin, and studied under Camille Saint-Saëns and César Franck. In 1862 she won first prize at the Paris Conservatory, where she was a student.

She married Alfred Jaëll in 1866, and she was then known variously as Marie Trautmann, Marie Jaëll, Marie Jaëll Trautmann or Marie Trautmann Jaëll. Together they gave concerts in Europe and Russia.

As a pianist, she specialized in the music of Schumann, Liszt, and Beethoven. She met Liszt in 1868, had lessons with him, was mentored by him, and helped him as a secretary for several weeks a year at Weimar late in his life.

Liszt introduced her to Johannes Brahms and Anton Rubinstein.
He wrote a set of variations on her Waltz for Piano, Four Hands, Op. 8.
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She also had composition lessons with César Franck and Camille Saint-Saëns, who dedicated his Piano Concerto No. 1 and the "Étude en forme de valse" to her.
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She was the first pianist to perform all the piano sonatas of Beethoven in Paris.

She did scientific studies of hand techniques in piano playing and attempted to replace traditional drilling with systematic piano methods.

Marie Jaëll composed pieces for piano, concertos, quartets, and others.
She dedicated her cello concerto to Jules Delsart.

Her students included Albert Schweitzer, who studied with her while also studying organ with Charles-Marie Widor in 1898-99.
She died in Paris.