Short answer
It depends on the dream. A good dream may be shared with someone you love or a wise person who can interpret it well. A bad dream should not be told to anyone. There is no authentic hadith listing 'four dreams you must never tell'. Lying about a dream is a serious sin.
Telling a good dream to a sincere, knowledgeable person is permitted and recommended; telling bad dreams is discouraged. Inventing a dream you did not see is haram.
The four schools agree on this.
Explanation
The Prophet ﷺ said that a good dream is from Allah: if you see something you like, tell it only to someone you love. If you see something you dislike, seek refuge in Allah, blow to your left and tell no one, for it will not harm you. In another narration he said to share it only with a friend or a person of sound judgement.
Why be careful? A jealous or careless person may give it a bad interpretation, spoil your happiness, or spread it. The Prophet Yaqub told Yusuf not to tell his brothers his dream, in case they plotted against him.
Posts online list 'four dreams you must never tell anyone', such as dreaming of the dead or of losing teeth. We know of no authentic hadith with such a list. The sunnah rule is simple: good dreams to the right people, bad dreams to no one.
Some cautions:
- Do not invent dreams. The Prophet ﷺ said whoever claims a dream he did not see will be made to tie two barley grains together, which he can never do. Claiming you saw a holy figure to win an argument or gain followers falls under this.
- Dreams are not proof. A dream cannot make something halal or haram, or prove a claim against someone.
- Choose interpreters carefully. Dream interpretation is a gift of knowledge and piety, not a free app or website. Allah taught it to Yusuf.
For what to do after a frightening dream, see after a bad dream. More in Dreams in Islam.
The evidence
Quran, Surah Yusuf 12:6
وَكَذَٰلِكَ يَجْتَبِيكَ رَبُّكَ وَيُعَلِّمُكَ مِن تَأْوِيلِ ٱلْأَحَادِيثِ وَيُتِمُّ نِعْمَتَهُۥ عَلَيْكَ وَعَلَىٰٓ ءَالِ يَعْقُوبَ كَمَآ أَتَمَّهَا عَلَىٰٓ أَبَوَيْكَ مِن قَبْلُ إِبْرَٰهِيمَ وَإِسْحَٰقَ ۚ إِنَّ رَبَّكَ عَلِيمٌ حَكِيمٌۭ ﴿٦﴾
And thus will your Lord choose you and teach you the interpretation of narratives and complete His favor upon you and upon the family of Jacob, as He completed it upon your fathers before, Abraham and Isaac. Indeed, your Lord is Knowing and Wise."
Interpreting dreams is knowledge given by Allah.
Sahih al-Bukhari 7044
Sahih... فلا يحدث به إلا من يحب ...
"Let him not tell it except to someone he loves."
Good dreams are shared only with people who wish you well.
Sunan Abi Dawud 5020
Graded sahih... الرؤيا على رجل طائر ما لم تعبر ...
"A dream is on the leg of a bird as long as it is not interpreted."
Interpretation matters, so share dreams with the wise.
Sahih al-Bukhari 7042
Sahih... من تحلم بحلم لم يره كلف أن يعقد بين شعيرتين ...
"Whoever claims to have seen a dream he did not see will be made to tie two barley grains together."
Lying about dreams is a serious sin.
Where the ruling is recorded
- Fath al-Bari (Ibn Hajar), Kitab al-Ta'bir. Explains whom dreams may be told to and the warning against invented dreams.
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.