Short answer
There is no verse or authentic hadith that gives a meaning for a dog bite in a dream, so we do not give one. A frightening dream like this is treated as a bad dream: seek refuge in Allah from Shaytan, turn onto your other side and do not tell people. It will not harm you.
Dream meanings are not binding and no ruling follows from them. A frightening dream is handled with the sunnah steps for bad dreams.
The four schools agree on this.
Explanation
The Prophet ﷺ taught that frightening dreams come from Shaytan, who wants to sadden the believer, and that they do not harm you if you seek refuge in Allah and keep them to yourself. A dog biting your hand, a lion chasing you, rats in your house or spiders on your body usually fall into this group, or come from your own fears.
Dream books, such as the one attributed to Ibn Sirin, give meanings for animals, but those meanings are the interpreters' own judgement, not revelation, and even they stressed that the same image can mean different things for different people. That is why no website or dream dictionary can tell you what your dream means.
What to do:
- blow lightly to your left three times and seek refuge in Allah from Shaytan and the dream's evil;
- turn onto your other side, and pray two rak'ahs if you wish;
- do not tell people about it, and do not worry that it is a warning;
- if the same dream keeps returning and troubles you, read the morning and evening adhkar and speak to a trusted scholar.
Dreams can reflect real fears. If you were bitten by a dog as a child, or a relationship is causing stress, your mind may show it this way. Take care of the real worry, and leave the dream. For snakes in dreams, see snakes in dreams. For the steps in detail, see after a bad dream.
The evidence
Sahih al-Bukhari 3292
Sahih... الرؤيا الصالحة من الله والحلم من الشيطان ...
"A good dream is from Allah and a bad dream is from Shaytan."
Frightening dreams are from Shaytan.
Sahih Muslim 2263
Sahih... ورؤيا تحزين من الشيطان ورؤيا مما يحدث المرء نفسه ...
"A dream that saddens is from Shaytan, and a dream is from what a person tells himself."
Many frightening dreams have no message.
Where the ruling is recorded
- Sharh Sahih Muslim (Nawawi), Kitab al-Ru'ya. The etiquette for bad dreams and the limits of interpretation.
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.