Hassan ibn Thabit (Arabic: حسان بن ثابت) (born c. 563, Medina died 674) was an Arabian poet and one of the companions of the Islamic prophet Muhammad, who was best known for poems in defense of the prophet.

He was born in Medina, and was a member of the Banu Khazraj tribe. Muhammad gave him a slave, Sirin as a concubine.

His writings in defense of Muhammad refer to contemporary events that have been useful in documenting the period. He was also Islam's first religious poet.