"O Guarani" is a Brazilian opera composed by Carlos Gomes in 1870. It is based on the novel of the same name by José de Alencar and tells the story of a love affair between a Portuguese nobleman and a native Guarani woman. The opera is set in the 16th century and explores themes of love, conflict, and cultural identity. The opera is notable for its incorporation of Brazilian musical elements and indigenous themes. It premiered in Teatro Municipal in Rio de Janeiro and has since become a significant work in the operatic repertoire, celebrated for its rich melodies and dramatic storytelling.