Short answer
Yes. Sex between a husband and wife is halal, and Islam treats it as a blessing that is even rewarded when done with a good intention. Outside marriage it is zina, a major sin. The four schools agree.
Intimacy within a valid nikah is permissible (mubah) and becomes an act of reward when the intention is chastity, love and children. Each spouse has a right to it, so neither should neglect the other without a valid reason.
The four schools agree on this.
Explanation
Islam does not see sexual desire as shameful, or as something holy people must give up. Allah calls spouses clothing for one another (2:187) and says He placed affection and mercy between them (30:21). Lifelong celibacy as a path of worship is not part of the sunnah: the Prophet ﷺ married, and said that whoever turns away from his sunnah is not from him.
Marriage is the one door through which this desire is lawful, and through that door it becomes worship. The Prophet ﷺ told his Companions that there is charity even in a man's intimacy with his wife. When they asked how fulfilling a desire could be rewarded, he answered that if it were put in something haram it would be a sin, so when it is put in what is halal it is rewarded.
- Only within nikah. Any sexual relationship outside a valid marriage is zina. See sex before marriage.
- Both spouses have rights. The husband should care for his wife's needs just as she cares for his. See refusing intimacy.
- A few clear limits. No intercourse during her period or postnatal bleeding, no anal intercourse, and none in the daytime of a fast or in ihram. These are set out in what is forbidden in intimacy.
- Privacy. What happens between spouses stays between them.
It is sunnah to begin with the dua before intercourse, and ghusl (the full ritual bath) is needed afterwards before the next prayer. See when ghusl is required.
The evidence
Quran, Surah Al-Baqara 2:187
أُحِلَّ لَكُمْ لَيْلَةَ ٱلصِّيَامِ ٱلرَّفَثُ إِلَىٰ نِسَآئِكُمْ ۚ هُنَّ لِبَاسٌۭ لَّكُمْ وَأَنتُمْ لِبَاسٌۭ لَّهُنَّ ۗ عَلِمَ ٱللَّهُ أَنَّكُمْ كُنتُمْ تَخْتَانُونَ أَنفُسَكُمْ فَتَابَ عَلَيْكُمْ وَعَفَا عَنكُمْ ۖ فَٱلْـَٰٔنَ بَٰشِرُوهُنَّ وَٱبْتَغُوا۟ مَا كَتَبَ ٱللَّهُ لَكُمْ ۚ وَكُلُوا۟ وَٱشْرَبُوا۟ حَتَّىٰ يَتَبَيَّنَ لَكُمُ ٱلْخَيْطُ ٱلْأَبْيَضُ مِنَ ٱلْخَيْطِ ٱلْأَسْوَدِ مِنَ ٱلْفَجْرِ ۖ ثُمَّ أَتِمُّوا۟ ٱلصِّيَامَ إِلَى ٱلَّيْلِ ۚ وَلَا تُبَٰشِرُوهُنَّ وَأَنتُمْ عَٰكِفُونَ فِى ٱلْمَسَٰجِدِ ۗ تِلْكَ حُدُودُ ٱللَّهِ فَلَا تَقْرَبُوهَا ۗ كَذَٰلِكَ يُبَيِّنُ ٱللَّهُ ءَايَٰتِهِۦ لِلنَّاسِ لَعَلَّهُمْ يَتَّقُونَ ﴿١٨٧﴾
It has been made permissible for you the night preceding fasting to go to your wives [for sexual relations]. They are clothing for you and you are clothing for them. Allah knows that you used to deceive yourselves, so He accepted your repentance and forgave you. So now, have relations with them and seek that which Allah has decreed for you. And eat and drink until the white thread of dawn becomes distinct to you from the black thread [of night]. Then complete the fast until the sunset. And do not have relations with them as long as you are staying for worship in the mosques. These are the limits [set by] Allah, so do not approach them. Thus does Allah make clear His ordinances to the people that they may become righteous.
Allah describes spouses as covering, comfort and protection for each other, and permits intimacy on the nights of Ramadan.
Quran, Surah Ar-Room 30:21
وَمِنْ ءَايَٰتِهِۦٓ أَنْ خَلَقَ لَكُم مِّنْ أَنفُسِكُمْ أَزْوَٰجًۭا لِّتَسْكُنُوٓا۟ إِلَيْهَا وَجَعَلَ بَيْنَكُم مَّوَدَّةًۭ وَرَحْمَةً ۚ إِنَّ فِى ذَٰلِكَ لَءَايَٰتٍۢ لِّقَوْمٍۢ يَتَفَكَّرُونَ ﴿٢١﴾
And of His signs is that He created for you from yourselves mates that you may find tranquillity in them; and He placed between you affection and mercy. Indeed in that are signs for a people who give thought.
Marriage and the closeness within it are counted among the signs of Allah.
Sahih Muslim 1006
Sahih... وفي بضع أحدكم صدقة ...
"And in the intimacy of one of you with his wife there is charity."
Lawful intimacy is rewarded like an act of charity.
Sahih al-Bukhari 5063
Sahih... فمن رغب عن سنتي فليس مني ...
"Whoever turns away from my sunnah is not from me."
Said to Companions who wanted to give up marriage for worship, showing that marriage is part of the sunnah.
Where the ruling is recorded
- al-Hidaya, Kitab al-Nikah, opening chapter. Nikah is a sunnah, and its aims include chastity and children.
- Radd al-Muhtar (Ibn Abidin), Kitab al-Nikah, opening discussion. Explains that nikah done with a good intention is among the acts of worship.
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.