Aisha bint Abi Bakr (c. 614 CE – July 678) was a muhadditha, political figure, and the third and youngest wife of Islamic prophet Muhammad.

Aisha played a significant role in early Islamic history, both during Muhammad's life and after his death. She is regarded in Sunni tradition as intelligent, inquisitive, and scholarly, and is often described as Muhammad's most beloved wife after Khadija bint Khuwaylid. She contributed to the transmission of Muhammad's teachings and remained active in the Muslim community for 44 years after his death. Aisha is credited with narrating over 2,000 hadiths, covering not only aspects of Muhammad's personal life but also legal, ritual, and theological subjects such as inheritance, pilgrimage, prayer, and eschatology. Her intellectual abilities and knowledge of poetry, medicine, and Islamic jurisprudence were praised by early scholars, including al-Zuhri and her student Urwa ibn al-Zubayr.

In addition to her scholarly contributions, Aisha was involved in the religious, social, and political affairs of the early Muslim community. During the caliphates of Abu Bakr, Umar, Uthman, and Ali, she engaged in public discourse, transmitted religious knowledge, and took part in major events, including the Battle of the Camel. Her participation in such matters was notable given the limited public roles generally held by women at the time. In Sunni Islam, she is revered as a leading scholar, hadith transmitter, and teacher of several companions and the tabi'in, while in Shia Islam, she is viewed critically for her opposition to Ali.

Aisha was born in Mecca c. 614. She was the daughter of Abu Bakr and Umm Ruman, two of Muhammad's companions. No sources offer much more information about Aisha's childhood years.

Muhammad reportedly stated that he saw Aisha twice in his dreams, being carried in a silk cloth by an angel who told him she would be his wife. He believed that if the dreams were from God, they would come true. Following the death of his first wife, Khadija bint Khuwaylid, his aunt Khawlah bint Hakim suggested that he marry Aisha. Aisha's father Abu Bakr was at first unsure about marrying his daughter to Muhammad; he thought they were brothers. Muhammad clarified that they were merely brothers in religion, and it was legal for him to marry Aisha. Aisha's engagement to Jubayr ibn Mut'im, a boy close to her age, was then annulled. Orientalist W. Montgomery Watt suggests that Muhammad hoped to strengthen his ties with Abu Bakr; the strengthening of ties commonly served as a basis for marriage in Arabian culture.

All extant hadiths agree that Aisha was married to Muhammad in Mecca, but that the marriage was not consummated until the month of Shawwal following his hijrah to Medina, in April 623. Some classical sources, however, state that the marriage itself took place in Medina, without mentioning any delay in consummation.

Classical Islamic sources state that Aisha was six at the time of her marriage with Muhammad and nine at the time of its consummation (then 50 or 53). In a hadith recorded in Sahih al-Bukhari, Aisha recalls being married at the age of six. Ibn Sa'd's biography holds her age at the time of marriage as between six and seven, and gives her age at consummation to be nine while Ibn Hisham's biography of Muhammad suggests she may have been ten years old at consummation. Al-Tabari notes Aisha to have stayed with her parents after the marriage and consummated the relationship at nine years of age since she was young and sexually immature at the time of marriage.

In Islamic literature, the young age of her marriage did not draw any significant discourse; nonetheless, Spellberg and Ali find the very mention of her age to be atypical of early Muslim biographers, and hypothesize a connotation to her virginity and, more than that, religious purity. Her age did not interest later Muslim scholars either, and went unremarked-upon even by medieval and early-modern Christian polemicists. Early Orientalist writers, even in their condescending approach towards Muhammad and Islam, were primarily concerned with Muhammad's embrace of polygamy and the ethics of marrying for political causes; the few who discussed Aisha's age chose to explain the age gap – without any condemnation – by citing the contemporary understanding of the Orient as a hot place, that promulgated sexually deviant practices.