Cahide Sonku (1916-1981)  is the first Turkish female director. She was actually a film and theatre star.
She assisted Seyfi Havaeri in The Altruist Mother/ Fedakar Anne (1949)
The Country and Namik Kemal/Vatan ve Namik Kemal, w/M. Ariburnu and S Ayanoglu (1951)
The Long Awaited Song/Beklenen Sarki, w/Ariburnu and Ayanoglu (1953) (title translations mine, as far as I know none of these films were distributed in English speaking countries)

But one must mention Bilge Olgac (1940-1994) who was killed in an accident just a few years ago. She began her career as a story writer and then wrote screenplays for important film makers. Yilmaz Guney starred in her first film.  She devoted some 29 years to directing. She even directed some action films but after the mid 80s she focussed on the oppressed women of the rural area. Deniz Derman gave a paper on her work in Antwerp last year. I can provide her e-mail address for those who are interested in  Olgac.

Another woman director I find important is Turkan Soray (1945-). Like Cahide Sonku, she is actually a film star, as matter of fact the "Sultan" of Turkish cinema since the late 50s. She is still performing and receiving positive criticism. She made four films, some of which were considered as examples of a kind of "harsh realism" like those of G Rocha.