Short answer
Yes. Marrying a first cousin, on the father's or the mother's side, is halal in Islam, and the four schools agree. Cousins are not among the relatives the Quran forbids. It is not obligatory or specially recommended, and couples with a family history of genetic illness may wish to seek medical advice.
Marriage to a first cousin (the child of a paternal or maternal uncle or aunt) is permissible (mubah). Cousins are not mahram, which is also why they must observe hijab and other rules with each other before marriage.
The four schools agree on this.
Explanation
Allah lists the women a man may not marry in 4:23: mothers, daughters, sisters, aunts, nieces, milk relatives, certain in-laws and two sisters together. Cousins are not on the list, and the next ayah says, "lawful to you are all others beyond these." In 33:50 Allah mentions the Prophet's ﷺ marriage to "the daughters of your paternal uncles and the daughters of your paternal aunts". He married Zaynab bint Jahsh, the daughter of his paternal aunt, and his daughter Fatimah married Ali, his paternal uncle's son.
Some points that follow:
- Because cousins can marry, they are not mahram to each other. A woman wears hijab in front of male cousins, and they should not be alone together.
- Islam does not require or prefer cousin marriage. It is a family choice, common in some cultures and rare in others.
- If both cousins were breastfed by the same woman in infancy (within two lunar years, by the Hanafi view on the period), they may be milk siblings and unable to marry. Check this with the family.
- Some scholars of the past preferred marrying outside the close family for stronger, healthier children, but there is no authentic hadith forbidding cousin marriage. Today, genetic counselling is a sensible step when the family has hereditary illness.
For more history and the medical side, read our longer article on cousin marriage in Islam. For the conditions of the contract itself, see conditions of a valid nikah.
The evidence
Quran, Surah An-Nisaa 4:23
حُرِّمَتْ عَلَيْكُمْ أُمَّهَٰتُكُمْ وَبَنَاتُكُمْ وَأَخَوَٰتُكُمْ وَعَمَّٰتُكُمْ وَخَٰلَٰتُكُمْ وَبَنَاتُ ٱلْأَخِ وَبَنَاتُ ٱلْأُخْتِ وَأُمَّهَٰتُكُمُ ٱلَّٰتِىٓ أَرْضَعْنَكُمْ وَأَخَوَٰتُكُم مِّنَ ٱلرَّضَٰعَةِ وَأُمَّهَٰتُ نِسَآئِكُمْ وَرَبَٰٓئِبُكُمُ ٱلَّٰتِى فِى حُجُورِكُم مِّن نِّسَآئِكُمُ ٱلَّٰتِى دَخَلْتُم بِهِنَّ فَإِن لَّمْ تَكُونُوا۟ دَخَلْتُم بِهِنَّ فَلَا جُنَاحَ عَلَيْكُمْ وَحَلَٰٓئِلُ أَبْنَآئِكُمُ ٱلَّذِينَ مِنْ أَصْلَٰبِكُمْ وَأَن تَجْمَعُوا۟ بَيْنَ ٱلْأُخْتَيْنِ إِلَّا مَا قَدْ سَلَفَ ۗ إِنَّ ٱللَّهَ كَانَ غَفُورًۭا رَّحِيمًۭا ﴿٢٣﴾
Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your father's sisters, your mother's sisters, your brother's daughters, your sister's daughters, your [milk] mothers who nursed you, your sisters through nursing, your wives' mothers, and your step-daughters under your guardianship [born] of your wives unto whom you have gone in. But if you have not gone in unto them, there is no sin upon you. And [also prohibited are] the wives of your sons who are from your [own] loins, and that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allah is ever Forgiving and Merciful.
The list of forbidden relatives does not include cousins.
Quran, Surah An-Nisaa 4:24
۞ وَٱلْمُحْصَنَٰتُ مِنَ ٱلنِّسَآءِ إِلَّا مَا مَلَكَتْ أَيْمَٰنُكُمْ ۖ كِتَٰبَ ٱللَّهِ عَلَيْكُمْ ۚ وَأُحِلَّ لَكُم مَّا وَرَآءَ ذَٰلِكُمْ أَن تَبْتَغُوا۟ بِأَمْوَٰلِكُم مُّحْصِنِينَ غَيْرَ مُسَٰفِحِينَ ۚ فَمَا ٱسْتَمْتَعْتُم بِهِۦ مِنْهُنَّ فَـَٔاتُوهُنَّ أُجُورَهُنَّ فَرِيضَةًۭ ۚ وَلَا جُنَاحَ عَلَيْكُمْ فِيمَا تَرَٰضَيْتُم بِهِۦ مِنۢ بَعْدِ ٱلْفَرِيضَةِ ۚ إِنَّ ٱللَّهَ كَانَ عَلِيمًا حَكِيمًۭا ﴿٢٤﴾
And [also prohibited to you are all] married women except those your right hands possess. [This is] the decree of Allah upon you. And lawful to you are [all others] beyond these, [provided] that you seek them [in marriage] with [gifts from] your property, desiring chastity, not unlawful sexual intercourse. So for whatever you enjoy [of marriage] from them, give them their due compensation as an obligation. And there is no blame upon you for what you mutually agree to beyond the obligation. Indeed, Allah is ever Knowing and Wise.
All women outside the list are lawful, cousins included.
Quran, Surah Al-Ahzaab 33:50
يَٰٓأَيُّهَا ٱلنَّبِىُّ إِنَّآ أَحْلَلْنَا لَكَ أَزْوَٰجَكَ ٱلَّٰتِىٓ ءَاتَيْتَ أُجُورَهُنَّ وَمَا مَلَكَتْ يَمِينُكَ مِمَّآ أَفَآءَ ٱللَّهُ عَلَيْكَ وَبَنَاتِ عَمِّكَ وَبَنَاتِ عَمَّٰتِكَ وَبَنَاتِ خَالِكَ وَبَنَاتِ خَٰلَٰتِكَ ٱلَّٰتِى هَاجَرْنَ مَعَكَ وَٱمْرَأَةًۭ مُّؤْمِنَةً إِن وَهَبَتْ نَفْسَهَا لِلنَّبِىِّ إِنْ أَرَادَ ٱلنَّبِىُّ أَن يَسْتَنكِحَهَا خَالِصَةًۭ لَّكَ مِن دُونِ ٱلْمُؤْمِنِينَ ۗ قَدْ عَلِمْنَا مَا فَرَضْنَا عَلَيْهِمْ فِىٓ أَزْوَٰجِهِمْ وَمَا مَلَكَتْ أَيْمَٰنُهُمْ لِكَيْلَا يَكُونَ عَلَيْكَ حَرَجٌۭ ۗ وَكَانَ ٱللَّهُ غَفُورًۭا رَّحِيمًۭا ﴿٥٠﴾
O Prophet, indeed We have made lawful to you your wives to whom you have given their due compensation and those your right hand possesses from what Allah has returned to you [of captives] and the daughters of your paternal uncles and the daughters of your paternal aunts and the daughters of your maternal uncles and the daughters of your maternal aunts who emigrated with you and a believing woman if she gives herself to the Prophet [and] if the Prophet wishes to marry her, [this is] only for you, excluding the [other] believers. We certainly know what We have made obligatory upon them concerning their wives and those their right hands possess, [but this is for you] in order that there will be upon you no discomfort. And ever is Allah Forgiving and Merciful.
Allah names cousins as lawful for the Prophet ﷺ to marry.
Where the ruling is recorded
- al-Hidaya, Kitab al-Nikah, Fasl fi Bayan al-Muharramat. The forbidden relatives are listed; cousins are not among them.
- al-Fatawa al-Hindiyya, Kitab al-Nikah, chapter on women forbidden in marriage. Lists blood, milk and in-law prohibitions.
This answer is pending review by the scholars on our team. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.