All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is permissible for a woman to divide her hair into two braids at the back of her head unless this is done as a way of imitating the non-Muslim or the dissolute women, or imitating men. The evidence of permissibility is that in principle all things are permissible, and we do not know any evidence that prohibits this. Rather, there is evidence that the Prophet divided his hair (into two). Ibn ‘Abbaas said: “The people of the Book used to let their hair hang down and the polytheists used to divide their hair and the Prophet used to like to do the same as the people of the Book unless he is ordered to differ from them, so, the Prophet let his forelock down and afterwards he would divide his hair.”
In his comment, An-Nawawi said: “To conclude, the correct opinion is that it is permissible to let the hair hang down or to divide it and dividing it is better.”
Allaah Knows best.