The Sultanate of Muscat and Oman (Arabic: سلطنة مسقط وعمان, romanized: Salṭanat Masqaṭ wa-‘Umān), also known briefly as the State of Muscat and Oman (Arabic: دولة مسقط وعمان, romanized: Dawlat Masqaṭ wa-‘Umān) during the rule of Taimur bin Faisal, was a sovereign state that encompassed the present-day Sultanate of Oman and parts of present-day United Arab Emirates and Pakistan, in the second half of the 19th century and 20th century.

In 1856, upon the death of the last ruler of the Omani Empire, Said bin Sultan, the empire split into two separate political entities: the Sultanate of Muscat and Oman and the Sultanate of Zanzibar. The former continued to be led by the Al Busaid dynasty, but transitioned into a new form of government after the palace coup of 23 July 1970 in which the sultan Said bin Taimur was immediately deposed in favour of his son Qaboos bin Said. The current Sultanate of Oman is the direct successor to the Sultanate of Muscat and Oman.

In medieval and early modern times, the area of southeastern Arabia was divided into 4 regions: Oman, Muscat, Dhofar, and the Pirate Coast.

Strictly speaking, Oman (Imamate of Oman, Arabic: عُمان الوسطى, ʿUmān al-Wusṭā) is the inner, continental part of the region without access to the coast and with the capital in the cities of Nizwa and Rustaq. Muscat is the coastal region looking onto the Gulf of Oman. Its rulers often carried out expansion, including overseas. Historical Muscat and Oman are separated by the Green Mountain plateau (Al Jabal Al Akhdar (Arabic: الجبل الأخضر)).

The third region is the so-called "Pirate Coast", later known as Treaty Oman (in reference to their allegiance to the United Kingdom), and is today the United Arab Emirates (UAE).

The fourth is Dhofar, an area south of the Rub' al-khali, east of the Hadhramaut mountains and west of the Hajar mountain ranges. Linguistically part of South Arabia, its inhabitants traditionally speak Modern South Arabian languages. Today it is made up of the Dhofar and the southern districts of Al-Wusta governorates of Oman.

Although there was a Portuguese presence in the region, the Yaruba imams expelled them in the 17th century. The imams later expanded their own maritime empire to the Persian Gulf and Zanzibar, expelling the Portuguese from the wider region, before falling to the Persians. Persian hegemony in Muscat and Oman was ended in 1749 by a defeat at the hands of the elected Imam Ahmad bin Said. The British Empire was keen to dominate southeast Arabia to curb the influence of other European powers and to weaken the Omani Empire in the 18th century. The British empire thus backed the Albusaidi Sultans of Muscat that came to power in the second half of the 18th century. The British empire established a series of treaties with the Sultans with the objective of increasing British political and economic influence over Muscat. The Sultanate eventually became increasingly dependent on British loans and political advice.

Historical differences always existed between the rich, seafaring coastal Sultanate of Muscat and the tribes of the interior.^{[citation needed]} Though the inland territories were under nominal control of the Sultans of Muscat, they were in practice run by tribal leaders and the Imams of Oman, practitioners of the Ibadi sect of Islam.^{[citation needed]}