Is it haram to cry when someone dies?

No. Crying is a natural mercy, and the Prophet ﷺ wept when his son died. What Islam forbids is loud wailing, hitting yourself, tearing your clothes or protesting against Allah's decree. Quiet tears, sadness and missing the person are all allowed.

The Prophet ﷺ cried

When his young son Ibrahim was dying, the Prophet's ﷺ eyes shed tears. Abdur-Rahman ibn Awf said, "O Allah's Messenger, even you are weeping!" He replied, "O Ibn Awf, this is mercy." Then he wept more and said: "The eyes are shedding tears and the heart is grieved, and we will not say except what pleases our Lord" (Sahih al-Bukhari 1303).

On another occasion he wept at the bedside of Sa'd ibn Ubadah and told the people: "Allah does not punish for shedding tears, nor for the grief of the heart, but He punishes or bestows His mercy because of this," and he pointed to his tongue (Sahih al-Bukhari 1304).

Prophets grieved too

The Quran describes the sorrow of Prophet Ya'qub (Jacob) when he lost his son Yusuf:

وَٱبْيَضَّتْ عَيْنَاهُ مِنَ ٱلْحُزْنِ فَهُوَ كَظِيمٌ "And his eyes turned white out of the grief he suppressed." Quran 12:84

Even a prophet with firm faith felt deep pain. Having tears does not mean having weak faith. See Is it okay for Muslim men to cry?

Where Islam draws the line

The Prophet ﷺ said: "He who slaps his cheeks, tears his clothes and follows the ways and traditions of the Days of Ignorance is not one of us" (Sahih al-Bukhari 1294). These actions are forbidden because they show anger at Allah's decree and cause harm. In practice this means:

No hitting yourself or tearing clothes.
No loud, ritual wailing (niyahah) or screaming at the person who died.
No words that object to Allah, such as "Why did Allah do this to me?" said in anger.

Saying "Inna lillahi wa inna ilayhi raji'un" and asking for patience is the Islamic response.

Patience does not mean not crying

The Prophet ﷺ once told a weeping woman at a grave to fear Allah and be patient. She did not know who he was and snapped at him. Later she came to apologise, and he said: "Verily, patience is at the first stroke of a calamity" (Sahih al-Bukhari 1283). True patience means holding on to Allah from the first moment, not hiding your tears.

If you cannot cry

Some people feel numb or cry later, and that is normal. Grief shows up differently in each person. If it feels too heavy, talk to someone you trust or a counsellor. See How do I deal with the loss of a loved one as a Muslim? and What does the Quran say about sadness?

Key points

Crying is mercy; the Prophet ﷺ wept (Sahih al-Bukhari 1303).
Allah does not punish for tears or grief of the heart (Sahih al-Bukhari 1304).
Wailing, hitting yourself and tearing clothes are forbidden (Sahih al-Bukhari 1294).
Patience is about your response to Allah, not about holding back tears.

Tip: Keep one simple dua ready for hard moments: "Inna lillahi wa inna ilayhi raji'un." Saying it quietly can help steady you when the tears come.