Emanuel "Manny" Ax (born June 8, 1949) is an American classical pianist. He is known for his chamber music collaborations with cellist Yo-Yo Ma and violinists Isaac Stern and Young Uck Kim, as well as his piano recitals and performances with major orchestras in the world.

Starting at age 12, Ax studied piano under Mieczysław Munz of the Juilliard School. He won honorable mention at the VIII International Chopin Piano Competition in 1970, third place at the Vianna da Motta International Music Competition in 1971, seventh place at the Queen Elisabeth Competition in 1972, and first prize in the Arthur Rubinstein International Piano Master Competition in 1974.

Ax has been a faculty member at the Juilliard School since 1990.

Ax was born into the Polish-Jewish family of Joachim and Hellen Ax in Lviv, Ukraine, formerly part of the Soviet Union. Both parents were Nazi concentration camp survivors. Ax began to study piano at the age of six; his father was his first piano teacher. When he was seven, the family moved to Warsaw, Poland, where he studied piano at the Miodowa school. Two years later, Ax's family moved to Winnipeg, Manitoba, Canada, where he continued to study music, including as a member of The Junior Musical Club of Winnipeg. In 1961, when Ax was 12 years old, the family moved to New York City, and Ax continued his piano studies under Mieczysław Munz of the Juilliard School until 1976, when Munz left New York to teach in Japan. In 1970, Ax received his B.A. in French at Columbia University and became an American citizen. The same year, he won honorable mention at the VIII International Chopin Piano Competition in Warsaw. In 1971, he won third place at the Vianna da Motta International Music Competition. In 1972, he placed 7th at the Queen Elisabeth Competition in Brussels. He caught the public eye when he won the Arthur Rubinstein International Piano Master Competition in 1974, where he was personally congratulated by renowned pianist Arthur Rubinstein, who was a judge for the competition. The New York Times reported on Ax's win in 1974 and said that in addition to a prize of $5,000, Ax "will receive the Artur Rubenstein Gold Medal engagements with the Israel Philharmonic and the BBC Orchestra, a recording contract with RCA and an artist‐management contract with Hurok Artists."

In 1975, Ax was named recipient of the Michaels Award of Young Concert Artists, and in 1979, he was named recipient of the Avery Fisher Prize.

Recalling his competition years, Ax said "You tend to forget how really awful the tension was. Here you were, No. 19, trying to play something better than No. 18. Ridiculous." For Ax, saying which pianist is better is only a subjective judgment at the highest levels, "can anyone really go to piano recital and say Horowitz is better than Rubinstein? The most I can say is that Rubinstein speaks to me with greater voice than this one or that one." Though he admits that competitions are a necessary means toward success for pianists, Ax hopes to never "sit on a jury and eliminate people".

When speaking about performance repertoire, Ax said that one should not perform at a concert with pieces they have only learned recently: "People think pianists are lazy because they play the same works again and again, but it's not that. It's being afraid of something you haven't done in public before. A conductor can do what he does very well whether his hands are cold or his baton is trembling. He can still get what he wants. But if I'm afraid, things will suffer. Physical and mental coordination must be perfect."

Ax has been the main duo recital partner of cellist Yo-Yo Ma since August 3, 1973, when the pair performed its first public recital at the Marlboro Music School and Festival. They have recorded much of the cello/piano repertoire together. Ax also played quartets briefly with Ma and violinists Isaac Stern and Jaime Laredo. Before the quartet disbanded in 2001 due to the death of Stern, they recorded works for Sony by Brahms, Fauré, Beethoven, Schumann and Mozart. Ax is also a featured guest artist in a documentary film about the Toronto Symphony Orchestra and Peter Oundjian, Five Days in September; the Rebirth of an Orchestra.