Question: “Is it permissible for a woman to change her family name to her husband’s family name?”
Has been answered by Shaykh Amjad Rasheed & translated by Shaykh Hamza Karamali of SunniPath.com
If, by changing her family name and ascribing herself to another family, she intends to absolve herself of and turn away from her lineal ascription to her own father from whose loins she came, and to make herself a daughter of that other family, then this is a major sin that is extremely forbidden. Its prohibition has been transmitted with rigorously authenticated (sahih) chains in Bukhari and Muslim and other collections of hadith. [The reason for its extreme prohibition] is that it comprises showing ungratefulness for one’s blessings, disregard for the rights of inheritance, kinship, reason, and other things, in addition to the severance of kinship ties and parental disobedience that it entails, as Imam Nawawi has explained.
If, however, the matter is not like this, but is merely an ascription of the wife’s name to her husband’s that some people have become habituated to doing without her intending to absolve herself of her lineal ascription to her father and adopting someone else as a father, then what is immediately apparent from the words of Imam Nawawi and others is that it is not forbidden and does not fall under the prohibition.
Imam Nawawi in his commentary on Sahih Muslim (2.50), commenting on the hadith, “There is nothing from a man who calls himself by other than his father except unbelief (kufr),” says, “The meaning of, calls himself by other than his father is ascribes himself to him and takes him as his father.” This implies that the one who does not take him as a father has not called himself by other than his father.
The great scholar Ibn ‘Allan al-Siddiqi says in his commentary on Riyad al-Salihin (8.614) in “The Chapter of Forbidden Matters” while talking about the above hadith,
“This means that he also intends to negate his paternal lineage from himself, for otherwise, if he is commonly known through the lineage of his grandfather or of the one who adopted him, for example, and he then ascribes himself to that because of its common knowledge among people, not intending to negate it from his own lineage, then the warning mentioned below does not apply to him.”
This is the same ruling in the Hanafi school, as understood from Imam Ayni’s commentary on Bukhari (Umdat al-Qari, 16.80) – Faraz Rabbani