Efrem Zimbalist, Sr. (9 April 1890 - February 22, 1985) was one of the world's most prominent concert violinists, as well as a composer, teacher, conductor and a long-time director of the Curtis Institute of Music.

Zimbalist was born in the southwestern Russian city of Rostov on Don (Rostov-na-Donu), Russia, the son of Jewish parents Maria (née Litvinoff) and Aron Zimbalist, who was a conductor. By the age of nine, Efrem Zimbalist was first violin in his father’s orchestra. At age 12 he entered the Saint Petersburg Conservatory and studied under Leopold Auer. He graduated from the St. Petersburg Conservatory in 1907 after winning a gold medal and the Rubenstein Prize, and by age 21 was considered one of the world's greatest violinists.

After graduation he debuted in Berlin (playing the Brahms concerto) and London in 1907 and in the U.S. in 1911, with the Boston Symphony Orchestra. He then settled in the U.S. He did much to popularize the performance of early music. In 1917, he was elected as an honorary member of Phi Mu Alpha Sinfonia, the national fraternity for men in music, by the fraternity's Alpha Chapter at the New England Conservatory of Music in Boston. In 1928, Zimbalist began teaching at the Curtis Institute of Music in Philadelphia. He was director of the school from 1941 to 1968. His pupils included such distinguished musicians as Oscar Shumsky, Felix Slatkin, Shmuel Ashkenasi, and Hidetaro Suzuki.