Alfred Denis Cortot (26 September 1877 – 15 June 1962) was a Franco-Swiss pianist and conductor. He was one of the most renowned classical musicians of the 20th century and especially valued for his poetic insight into Romantic piano works, particularly those of Chopin, Saint-Saëns and Schumann.

As one of the most celebrated piano interpreters of Chopin, Schumann and Debussy, Cortot produced printed editions of the piano works of all three, notable for their inclusion of meticulous commentary on technical problems and matters of interpretation.

Cortot suffered from memory lapses in concert (particularly notable from the 1940s onwards), and often left wrong notes on his records. When in form, however, he showed a brilliant technique that could handle almost any kind of pianistic firework. This gift is evident in his legendary recordings of Liszt's Sonata in B minor (the first recording ever made of this masterwork) and Saint-Saëns' Etude en forme de valse. The latter thoroughly impressed even Vladimir Horowitz, who approached Cortot to learn his "secret" in performing it; Cortot, however, did not divulge it to him. He recorded more of Chopin than of any other composer, and his performances of Chopin's Piano Concerto No. 2 in F minor with conductor Sir John Barbirolli and Saint-Saëns' Piano Concerto No. 4 in C minor under Charles Munch, both originally issued on RCA Victor/HMV 78s but reissued on CD in the Naxos Historical series (among others) rank among the all-time great concerto recordings.

He also wrote a good deal of didactic prose, including a piano primer: Rational Principles of Pianoforte Technique. This book contains many finger exercises to aid in the development of various aspects of piano playing technique. It was originally written in French but has long since been translated into other languages.

Technical flaws notwithstanding, Cortot was among the very greatest musicians of the century, and his recordings and musical annotations have seldom been out of print.

In the 1920s, Cortot recorded a number of piano rolls for the Aeolian/Duo-Art company, since 78 rpm discs were not always satisfactory in quality or maximum duration of the recording. Once he performed a Liszt Rhapsody weaving his own playing live at the piano with its mechanical reproduction. With eyes closed, some critics could not distinguish between the two. Later Cortot switched to disc technology, and he recorded right up to 1957, only five years before his death. In addition to his many recordings of works by Chopin, Schumann, and Liszt, he made important recordings of music by Weber, Mendelssohn, Franck, Debussy and others, and conducted his Ecole Normale orchestra (with a full nineteenth-century string complement) in a complete recording of the Brandenburg Concertos for RCA Victor in the early 1930s, in which he performed the lengthy solo cadenza of No. 5 in D major, on a modern piano in the grand Romantic manner yet exceedingly effectively in that admittedly archaic style, ending in a grand ritardando and rolled concluding D major chord as the orchestra re-entered with the concluding ritornello. He is also famous for his several trio recordings with Jacques Thibaud and Pablo Casals. Less famously but more appropriately and exquisitely styled, he accompanied singers such as Maggie Teyte and Charles Panzéra. There is even a late recording of Schumann's Dichterliebe in which he accompanied Gerard Souzay, of which the singer said, laconically, 'He was too old, and I was too young'. His final, postwar solo recordings are marred by more frequent technical slips, but he retained his uniquely eloquent phrasing and the free, Romantic performing manner for which he was famous.