It is closely related to the Sardinian warbler (Curruca melanocephala) of the Mediterranean basin and is similar to it in appearance.

The male of the nominate subspecies C. m. mystacea is dark greyish above and whitish below with a white submoustachial stripe and a pink throat and breast.

It is similar to female Sardinian and eastern subalpine warblers but has plainer tertial feathers and more contrast between the pale back and dark tail.

The subspecies C. m. mystacea breeds from the Caspian Sea region of Russia down through Georgia, Armenia, Azerbaijan and easternmost Turkey to northern Iran.

C. m. rubescens breeds locally in south-east Turkey, Syria, Iraq, western Iran and possibly in Lebanon.

C. m. turcmenica occurs from north-east Iran eastward to the Syr Darya valley in Central Asia and the Balochistan region in Pakistan.

The winter range covers southern Iran, the Arabian Peninsula and Northeast Africa, from Sudan to Somalia.

A few birds pass through Israel and Jordan on migration, and vagrants have been recorded from Portugal, Nigeria and Niger.