Threni: id est Lamentationes Jerimiæ Prophetæ

Threni: id est Lamentationes Jeremiae Prophetae, usually referred to simply as Threni, is a musical setting by Igor Stravinsky of verses from the Book of Lamentations in the Latin of the Vulgate, for solo singers, chorus and orchestra. It is Stravinsky's first and longest completely dodecaphonic work, but is not often performed. It has been called "austere" but also a "culminating point" in his career, "important both spiritually and stylistically" and "the most ambitious and structurally the most complex" of all his religious compositions, and even "among Stravinsky's greatest works".

Stravinsky composed Threni in 1957–58 for the Venice Biennale, and it was first performed there in September 1958. A performance in Paris two months later was a disaster, attributed to inadequate performers and insufficient rehearsals. It led to mutual recriminations between Stravinsky, Pierre Boulez, and Robert Craft. Threni was first published in 1958 and first recorded in 1959, conducted by the composer.