Ira B. Arnstein (born Itzig Arenstein April 12, 1879 – September 13, 1956) was a musical composer, songwriter, and "chronic litigator".
Arnstein was born in Litzingen, Russia (now Letychiv Ukraine), the son of Bernard Solomon Arnstein and Sophia (Sophie) Kozovoc. He emigrated to the United States when he was eleven. He studied piano at Scharwenka Conservatory in New York. He composed mainly "parlor piano pieces and Yiddish songs", once writing a Jewish national anthem entitled "Soldiers of Zion".