I Lituani (The Lithuanians) is an opera consisting of a prologue and three acts by Amilcare Ponchielli to an Italian libretto by Antonio Ghislanzoni, based on the historical poem Konrad Wallenrod written by Lithuanian-Polish poet Adam Mickiewicz.

The opera was extremely well received when it opened, and a second, final version with additional material was performed again a year later also to good reviews.

Arnoldo and Walter return and announce a heinous betrayal by Vitoldo, one of their leaders, which has led to the defeat of the Lithuanian army.

Walter tells his wife about his plan to defeat the Teutonic Knights, and swears his eternal love for her before leaving to avenge the Lithuanians.

Arnoldo and Aldona, disguised as bards, sing about the sad fate of Lithuania, predicting its imminent liberation.

Rather than falling into enemy hands, Walter drinks poison and exults in the victory of the Lithuanians, asking Albano to give Aldona his last farewell.