Abul-Qâsem Ferdowsi Tusi (; 940 – 1019/1025), also Firdawsi or Ferdowsi (), was a Persian poet and the author of Shahnameh ("Book of Kings"), which is one of the world's longest epic poems created by a single poet, and the greatest epic of Persian-speaking countries. Ferdowsi is celebrated as one of the most influential figures of Persian literature and one of the greatest in the history of literature.
Except for his kunya ( – Abo'l-Qâsem) and his laqab ( – Ferdowsī, meaning 'paradisic'), nothing is known with any certainty about his full name. From an early period on, he has been referred to by different additional names and titles, the most common one being حکیم / Ḥakīm ("philosopher"). Based on this, his full name is given in Persian sources as / Ḥakīm Abo'l-Qâsem Ferdowsī Țusī. Due to the non-standardised transliteration from Persian into English, different spellings of his name are used in English works, including Firdawsi, Firdusi, Firdosi, Firdausi, etc. The Encyclopaedia of Islam uses the spelling Firdawsī, based on the standardised transliteration method of the German Oriental Society. The Encyclopædia Iranica, which uses a modified version of the same method (with a stronger emphasis on Persian intonations), gives the spelling Ferdowsī. In both cases, the -ow and -aw are to be pronounced as a diphthong ([aʊ̯]), reflecting the original Arabic and the early New Persian pronunciation of the name. The modern Tajik transliteration of his name in Cyrillic script is Ҳаким Абулқосим Фирдавсӣ Тӯсӣ.
Ferdowsi was born into a family of Iranian landowners (dehqans) in 940 in the village of Paj, near the city of Tus, in the Khorasan region of the Samanid Empire, which is located in the present-day Razavi Khorasan Province of northeastern Iran. Little is known about Ferdowsi's early life. The poet had a wife, who was probably literate and came from the same dehqan class. He had a son, who died at the age of 37, and was mourned by the poet in an elegy which he inserted into the Shahnameh.
Ferdowsi belonged to the class of dehqans.