The moustached warbler (Acrocephalus melanopogon) is an Old World warbler in the genus Acrocephalus. It breeds in southern Europe and southern temperate Asia with a few in north-west Africa. It is partially migratory.
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 and also feeds on water snails.
The song is fast and similar to the 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 the nightingale. Unlike the sedge warbler, it does not sing in flight.