Short answer
Not while you are married to your wife. Having two sisters as wives at the same time is haram, and so is a woman together with her paternal or maternal aunt. If your wife dies, or you divorce her and her iddah ends, you may marry her sister. In the Hanafi school you wait for the iddah even after a final divorce.
Combining two sisters, or a woman and her aunt, in marriage is haram, and a second nikah while the first wife is still married to him or in any iddah from him is invalid. After the wife's death, or after her iddah from any kind of divorce has ended, marrying her sister is permissible.
Other madhhabs
- Shafi'i
- After a final (ba'in) divorce he may marry her sister during the first wife's iddah. The wait applies only after a revocable divorce.
- Maliki
- As the Shafi'is: after a final divorce he need not wait for the iddah to end.
Explanation
The ayah that lists the women a man cannot marry ends with "and that you take two sisters simultaneously" (4:23). The Prophet ﷺ added that a woman may not be married together with her paternal aunt or her maternal aunt. The scholars give the rule: any two women who could not marry each other if one were a man may not be co-wives. The wisdom is to protect close family bonds from the rivalry between co-wives.
- While married to her: a nikah with her sister is invalid.
- If she has died: he may marry her sister straight away, since a man has no iddah.
- If he divorced her: in the Hanafi school he waits until her iddah ends, whatever the type of talaq.
- If he married both: in one contract both are void; in two contracts the second is void.
Other in-laws. His wife's sister is not his mahram, so the rules of modesty and not being alone together apply. His wife's mother is permanently forbidden to him once the nikah is made. His brother's wife is not forbidden: he may marry her after his brother's death or divorce, once her iddah ends. See who a man may not marry and in-laws and mahrams.
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.
Two sisters may not be wives at the same time.
Sahih al-Bukhari 5109
Sahih... لا يجمع بين المرأة وعمتها ولا بين المرأة وخالتها ...
"A woman may not be married together with her paternal aunt, nor with her maternal aunt."
Extends the rule to a woman and her aunt.
Where the ruling is recorded
- al-Hidaya, Kitab al-Nikah, Fasl fi Bayan al-Muharramat. Combining two sisters is forbidden, including during the iddah of one of them.
- Minhaj al-Talibin (Nawawi), Kitab al-Nikah, chapter on the women forbidden in marriage. The Shafi'i view that he may marry the sister during the iddah of a final divorce.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. 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.