Iolanta (sometimes Iolanthe) () is a one-act opera. The libretto was written by Modest Tchaikovsky. It is based on the Danish play "Kong Renés Datter" ("King René’s Daughter") by Henrik Hertz. The story is a account of the life of Yolande de Bar. The play was translated by Fyodor Miller and adapted by Vladimir Zotov. The music was composed by Pyotr Ilyich Tchaikovsky. The opera received its premiere in St. Petersburg on 18 December 1892 at the Mariinsky Theatre on a double-bill with the ballet "The Nutcracker".