Ibn Khaldūn or Ibn Khaldoun (full name, Arabic: أبو زيد عبد الرحمن بن محمد بن خلدون الحضرمي ‎, Abū Zayd ‘Abdu r-Raḥmān bin Muḥammad bin Khaldūn Al-Ḥaḍrami, May 27, 1332 AD/732 AH – March 19, 1406 AD/808 AH) was a Muslim historiographer and historian who is often viewed as one of the forerunners of modern historiography,sociology and economics.

He is best known for his Muqaddimah (known as Prolegomenon in English), which was discovered, evaluated and fully appreciated first by 19th century European scholarship, although it has also had considerable influence on 17th-century Ottoman historians like Ḥajjī Khalīfa and Mustafa Naima who relied on his theories to analyze the growth and decline of the Ottoman empire. Later in the 19th century, Western scholars recognized him as one of the greatest philosophers to come out of the Muslim world.

Ibn Khaldun's life is relatively well-documented, as he wrote an autobiography (التعريف بابن خلدون ورحلته غربا وشرقا; Al-Taʻrīf bi Ibn-Khaldūn wa Riħlatuhu Gharbān wa Sharqān) in which numerous documents regarding his life are quoted word-for-word. However, the autobiography has little to say about his private life, so little is known about his family background. Generally known as "Ibn Khaldūn" after a remote ancestor, he was born in Tunis in AD 1332 (732 A.H.) into an upper-class Andalusian family, the Banū Khaldūn. His family, which held many high offices in Andalusia, had emigrated to Tunisia after the fall of Seville to Reconquista forces around the middle of the 13th century. Under the Tunisian Hafsid dynasty some of his family held political office; Ibn Khaldūn's father and grandfather however withdrew from political life and joined a mystical order. His brother, Yahya Ibn Khaldun, was also a historian who wrote a book on the Abdalwadid dynasty, and who was assassinated by a rival for being the official historiographer of the court.