Question: What is the ruling regarding a woman having hair extensions?
Response: It is haraam for a woman to have hair extensions using (real) hair or that which resembles (real) hair for the authentic evidences which mention this (prohibition).
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet (sal-Allaahu `alayhe wa sallam) and his family and his companions.
The Permanent Committee for Islaamic Research and Fataawa
Head: Shaykh ‘Abdul ‘Azeez Ibn Abdullaah Ibn Baaz;
Deputy Head: Shaykh ‘Abdur-Razzaaq ‘Afeefee;
Member: Shaykh ‘Abdullaah Ibn Ghudayyaan
Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa., – Volume 5, Page 193, Question 10 of Fatwa No.9850;
Fataawa wa Ahkaam fee Sha’r an-Nisaa – Question 5, Page 8. fatwaonline.com