Moustached Warbler, Acrocephalus melanopogon, is an Old World warbler in the genus Acrocephalus. It breeds in southern Europe and southern temperate Asia. It is partially migratory. South west European birds are resident, south east European birds winter in the Mediterranean breeding range, and the Asiatic race migrates to Arabia and India.

It is scarce north of its range, but has occurred as very a rare vagrant to Great Britain.

This passerine bird is a species found in upright vegetation such as reeds and sedge. 3-6 eggs are laid in a nest in a bush.

This is a medium-sized warbler, 12-13.5 cm long, slightly larger than the similar Sedge Warbler, Acrocephalus shoenabaenus. The adult has a finely streaked brown back and white underparts. The forehead is flattened, there is a prominent whitish supercilium, grey ear coverts, and the bill is strong and pointed.

The sexes are identical, as with most warblers, but young birds are more heavily streaked and have markings on the breast. Like most warblers, it is insectivorous.

The song is fast and similar to Sedge Warbler and Reed Warbler, with some mimicry and typically acrocephaline whistles added. Its song is softer and more melodious than those of its relatives, and includes phrases reminiscent of Nightingale.