"O Captain! My Captain!" is a famous elegy written by American poet Walt Whitman in 1865, shortly after the assassination of President Abraham Lincoln. The poem uses the metaphor of a ship’s captain who has died just as his vessel has safely reached port, symbolizing Lincoln’s leadership through the Civil War and his tragic death just as the Union was preserved.

Whitman, a great admirer of Lincoln, originally published the poem in The Saturday Press and later included it in his collection Leaves of Grass, though its more traditional style contrasts with his usual free verse. The poem's rhyme and meter, along with its patriotic and emotional tone, made it one of Whitman's most popular and accessible works—especially in classrooms and public readings.

"O Captain! My Captain!" endures as a poignant reflection on leadership, loss, and national grief.