Leopold Mordkhelovich Godowsky Sr. (/ɡəˈdɔːfski, ɡɔː-/; 13 February 1870 – 21 November 1938) was a virtuoso pianist, composer and teacher, born in what is now Lithuania to Jewish parents, who became an American citizen in 1891. He was one of the most highly regarded performers of his time, known for his theories concerning the application of relaxed weight and economy of motion within pianistic technique – principles later propagated by his pupils, such as Heinrich Neuhaus.

He was heralded among musical giants as the "Buddha of the Piano". Ferruccio Busoni claimed that he and Godowsky were "the only composers to have added anything of significance to keyboard writing since Franz Liszt."

As a composer, Godowsky is best known for his Java Suite, Triakontameron, Passacaglia and Walzermasken, alongside his transcriptions of works by other composers; the best-known of these works are the 53 Studies on Chopin's Études (1894–1914).

Leopold Godowsky was born in Žasliai (then Vilna Governorate, Russian Empire, now Lithuania) to Jewish parents, Mordkhel Godowsky (1848–1872), from Merkinė, and Khana-Sheyna Godowsky (née Levin, 1848–1918), from Gelvonai. His parents were married on 4 December 1868 in Širvintos. Godowsky's father, a respected feldsher, died in a cholera epidemic only eighteen months after his son's birth, and Leopold was raised by his mother and foster-parents, Louis and Minna Passinock, in Vilnius.

His talent manifested itself very early, and by age five Godowsky was already composing and becoming proficient on both piano and violin. He gave his first concert at age nine, and toured throughout Lithuania and East Prussia soon afterwards. Although he received a few lessons in his childhood, Godowsky was almost completely self-taught. Godowsky wrote in his autobiographical fragment, Retrospect:

I would be very glad could I have stated with truth that I was a pupil of [Franz] Liszt or any other great man, but I was not. I have not had three months lessons in my life. I have been told I was playing the piano before I was two. I think, however, an imaginative family perpetrated this story. I cannot vouch for the truth one way or the other. I have had some extraordinary experience, and this may have happened. I do not remember whether anybody taught me the value and meaning of notes and the use of the fingers of the keyboard, or whether I acquired my knowledge in an autodidactic way, but I do remember that I had no help from my fifth year on.

After briefly studying under Ernst Rudorff at the Königliche Hochschule für Musik in Berlin he left for the United States, where he made his first concert appearance in Boston in 1884. In 1885–86 Godowsky continued his American career, first playing at the New York Casino, and then, in 1886, embarking on a large tour of north-eastern US and Canada with violinist Ovide Musin. In 1887 he returned to Europe and gave numerous recitals in Paris and London, eventually becoming a protégé and friend of Camille Saint-Saëns.

In 1890 he returned to the United States and began a pedagogical career by joining the staff of the New York College of Music. On 30 April 1891 Godowsky married Frieda Saxe, a childhood friend, and the day after his marriage became a citizen of the United States. In 1891–93 he held a teaching position at the Gilbert Raynolds Combs's Broad Street Conservatory in Philadelphia, and then settled in Chicago, where he taught at the Chicago Conservatory. By the late 1890s Godowsky was extremely well known in North America.