"Dover Beach" is a lyric poem by the English poet Matthew Arnold. It was first published in 1867 in the collection New Poems; however, surviving notes indicate its composition may have begun as early as 1849. The most likely date is 1851.

The title, locale and subject of the poem's descriptive opening lines is the shore of the English ferry port of Dover, in Kent, facing Calais, in France, at the Strait of Dover, the narrowest part (21 miles (34 km)) of the English Channel, where Arnold spent his honeymoon in 1851. Many of the beaches in this part of England are made up of small stones or pebbles rather than sand, and Arnold describes the sea ebbing over the stones as a "grating roar".

In Stefan Collini's opinion, "Dover Beach" is a difficult poem to analyze, and some of its passages and metaphors have become so well known that they are hard to see with "fresh eyes". Arnold begins with a naturalistic and detailed nightscape of the beach at Dover in which auditory imagery plays a significant role ("Listen! you hear the grating roar"). The beach, however, is bare, with only a hint of humanity in a light that "gleams and is gone". Reflecting the traditional notion that the poem was written during Arnold's honeymoon (see composition section), one critic notes that "the speaker might be talking to his bride". Because Arnold was known for his discontent with the current state of society during his time, this poem is coming from the point of view of a man who feels as though society is not as beautiful as it once was. However, he sees a glimmer of hope through his lover.

The sea is calm to-night,
The tide is full, the moon lies fair
Upon the straits;—on the French coast, the light
Gleams, and is gone; the cliffs of England stand,
Glimmering and vast, out in the tranquil bay.
Come to the window, sweet is the night-air!
Only, from the long line of spray
Where the sea meets the moon-blanched land,
Listen! you hear the grating roar
Of pebbles which the waves draw back, and fling,
At their return, up the high strand,
Begin, and cease, and then again begin,
With tremulous cadence slow, and bring
The eternal note of sadness in.

— Lines 1–14

Arnold looks at two aspects of this scene, its soundscape (in the first and second stanzas) and the retreating action of the tide (in the third stanza). He hears the sound of the sea as "the eternal note of sadness". Sophocles, a 5th-century BC Greek playwright who wrote tragedies on fate and the will of the gods, also heard this sound as he stood upon the shore of the Aegean Sea. Critics differ widely on how to interpret this image of the Greek classical age. One sees a difference between Sophocles interpreting the "note of sadness" humanistically, while Arnold, in the industrial nineteenth century, hears in this sound the retreat of religion and faith. A more recent critic connects the two as artists, Sophocles the tragedian, Arnold the lyric poet, each attempting to transform this note of sadness into "a higher order of experience".

Sophocles long ago
Heard it on the Ægæan, and it brought
Into his mind the turbid ebb and flow
Of human misery; we
Find also in the sound a thought,
Hearing it by this distant northern sea.

— Lines 15–20