Sheikh `Abd al-Wahhâb al-Turayrî, former professor at al-Imâm University in Riyadh
I`tikâf is Sunnah for both men and women. It is authentically established that the Prophet (peace be upon him) performed i`tikâf in Ramadan and specifically during the last ten days of Ramadan, and some of his wives used to join him in i`tikâf. They continued to perform i`tikâf after he died.
However, a woman may not perform i`tikâf in her house, since i`tikâf is by definition a devotional retreat in the mosque. She may observe i`tikâf in the mosque if the mosque has an area set aside for women and she knows that she will not be confronted by any dangers, trials, or temptations.
And Allah knows best.
Source: Islam Today