The Hashemites (Arabic: الهاشميون, romanized: al-Hāshimiyyūn), officially the House of Hashim, are the royal family of Jordan, which they have ruled since 1921, and were the royal family of the kingdoms of Hejaz (1916–1925), Syria (1920), and Iraq (1921–1958). The family had ruled the city of Mecca continuously from the 10th century, frequently as vassals of outside powers, and ruled the thrones of the Hejaz, Syria, Iraq, and Jordan following their World War I alliance with the British Empire.

The family belongs to the Dhawu Awn, one of the branches of the Ḥasanid Sharifs of Mecca, also referred to as Hashemites. Their eponymous ancestor is traditionally considered to be Hashim ibn Abd Manaf, great-grandfather of the Islamic prophet Muhammad. Another claimed ancestor is Ali ibn Abi Talib, the usurped successor of the prophet Muhammad according to Shia Islam. The Ḥasanid Sharifs of Mecca (from whom the Hashemite royal family is directly descended), including the Hashemites' ancestor Qatadah ibn Idris, were Zaydī Shīʿas until the late Mamluk or early Ottoman period, when they became followers of the Shāfiʿī school of Sunnī Islam.

The current dynasty was founded by Sharif Hussein ibn Ali, who was appointed as Sharif and Emir of Mecca by the Ottoman sultan Abdul Hamid II in 1908, then in 1916—after concluding a secret agreement with the British Empire—was proclaimed King of Arab countries (but only recognized as King of the Hejaz) after initiating the Arab Revolt against the Ottoman Empire. His sons Abdullah and Faisal assumed the thrones of Jordan and Iraq in 1921, and his first son Ali succeeded him in the Hejaz in 1924. This arrangement became known as the "Sharifian solution". Abdullah was assassinated in 1951, but his descendants continue to rule Jordan today. The other two branches of the dynasty did not survive; Ali was ousted by Ibn Saud after the British withdrew their support from Hussein in 1924–1925, and Faisal's grandson Faisal II was executed in the 1958 Iraqi coup d'état.

According to historians Ibn Khaldun and Ibn Hazm, in c. 968 Ja'far ibn Muhammad al-Hasani came from Medina and conquered Mecca in the name of the Fatimid caliph al-Mu'izz, after the latter had conquered Egypt from the Ikhshidids. Jafar was from the wider Banu Hashim clan, albeit a different branch to the modern dynasty. The Banu Hashim claim to trace their ancestry from Hashim ibn Abd Manaf (died c. 497 AD), the great-grandfather of Muhammad, although the definition today mainly refers to the descendants of Fatimah bint Asad and her son Ali ibn Abi Talib, the usurped successor of the prophet Muhammad according to Shia Islam.

Control of Mecca remained with the clan; when the Ottoman Turks took control of Egypt in 1517 AD, Sharif Barakat quickly recognized the change in sovereignty, sending his son Abu Numayy II to the Ottoman sultan Selim I in Cairo, bearing the keys to the holy cities and other gifts. The Ottoman sultan confirmed Barakat and Abu Numayy in their positions as co-rulers of the Hejaz.

Before World War I, Hussein bin Ali of the Hashemite Dhawu-'Awn clan ruled the Hejaz on behalf of the Ottoman sultan. For some time it had been the practice of the Sublime Porte to appoint the Emir of Mecca from among a select group of candidates. In 1908, Hussein bin Ali was appointed to the Sharifate of Mecca. He found himself increasingly at odds with the Young Turks in control at Istanbul, while he strove to secure his family's position as hereditary emirs. Hussein bin Ali's lineage and destined position as the Sharif of Mecca helped foster the ambition for an independent Arab kingdom and caliphate. These pretensions came to the Ottoman rulers' attention and caused them to "invite" Hussein to Istanbul as the guest of the sultan in order to keep him under direct supervision. Hussein brought his four sons, Ali, Abdullah, Faisal, and Zeid, with him. It was not until after the Young Turk Revolution that he was able to return to the Hijaz and was officially appointed the Sharif.

Of Hussein's four sons, Abdullah was the most politically ambitious and became the planner and driving force behind the Arab revolt. Abdullah received military training in both the Hijaz and Istanbul. He was the deputy for Mecca in the Ottoman Parliament between 1912 and 1914. During this period, Abdullah developed deep interest in Arab nationalism and linked his father's interest for autonomous rule in the Hijaz to complete Arab emancipation. In 1914 he met the British high commissioner, Lord Kitchener, in Cairo to discuss the possibility of the British supporting an Arab uprising against the Turks. The possibility of co-operation was raised but no commitment was made by either side. Shortly after Abdullah returned to Mecca, he became his father's foreign minister, political advisor, and one of the commanders of the Arab Revolt.

Faisal, Hussein's third son, played an active role in the revolt as commander of the Arab army, while the overall leadership was placed in the hands of his father. The idea of an Arab uprising against the Ottoman Empire was first conceived by Abdullah. Only after gradual and persistent nudging did Abdullah convince his father, the conservative Sharif of Mecca, to move from the idea of home rule of a portion of Arabia within the Ottoman Empire to complete and total independence of the entire Empire's Arab provinces. Hussein recognized the necessity of breaking away from the Empire in the beginning of 1914 when he realized that he would not be able to complete his political objectives within the framework of the Ottomans. To have any success with the Arab revolt, the backing of another great power was crucial.