Ef (Ф, ф) is the twenty-first letter of the Cyrillic alphabet. It represents , a voiceless labiodental fricative.

It was directly derived from the Greek letter phi (Φ). Additionally, it has replaced Fita () in the Russian version of the alphabet since 1918. Unlike phi, however, it is transliterated as "f", not "ph".

See also

For the latin alphabet letter, see F.

Ф | Ef (cyrillique) | Ф (Cirillico) | Ф | Ф | Ф (кириллица) | Ф (ћириличко) | Ф | Ф