The Rime of the Ancient Mariner (originally The Rime of the Ancyent Marinere) is the longest major poem by the English poet Samuel Taylor Coleridge, written in 1797–98 and was published in 1798 in the first edition of Lyrical Ballads. Modern editions use a later revised version printed in 1817 that featured a gloss. Along with other poems in Lyrical Ballads, it was a signal shift to modern poetry and the beginning of British Romantic literature.

It relates the events experienced by a mariner who has returned from a long sea voyage. The Mariner stops a man who is on the way to a wedding ceremony and begins to narrate a story. The Wedding-Guest's reaction turns from bemusement to impatience and fear to fascination as the Mariner's story progresses, as can be seen in the language style: for example, Coleridge uses narrative techniques such as personification and repetition to create either a sense of danger, of the supernatural or of serenity, depending on the mood of each of the different parts of the poem.