The Gulf of Oman or Sea of Oman (Arabic: خليج عُمان‎—Ḫalīdj ʾUmān; alternatively known as خليج مکران—, Ḫalīdj Makrān; in Persian: دریای عمان Daryā-ye Ommān, or دریای پارس Daryā-ye Pārs) is a strait (and not an actual gulf) that connects the Arabian Sea with the Strait of Hormuz, which then runs to the Persian Gulf. It is generally included as a branch of the Persian Gulf, not as an arm of the Arabian Sea. The gulf borders Pakistan and Iran on the north, Oman on the south, and the United Arab Emirates on the west.

The International Hydrographic Organization defines the limits of the Gulf of Oman as follows:

On the Northwest. A line joining Ràs Limah (25°57'N) on the coast of Arabia and Ràs al Kuh (25°48'N) on the coast of Iran (Persia)

On the Southeast. The Northern limit of the Arabian Sea [A line joining Ràs al Hadd, East point of Arabia (22°32'N) and Ràs Jiyùni (61°43'E) on the coast of Pakistan].

Coordinates: 25°N 58°E / 25°N 58°E / 25; 58

Oman (ⁱ/oʊˈmɑːn/ oh-MAAN; Arabic: عمان‎ ʻUmān), officially called the Sultanate of Oman (Arabic: سلطنة عُمان‎ Salṭanat ʻUmān), is an Arab state in southwest Asia on the southeast coast of the Arabian Peninsula. It is bordered by the United Arab Emirates (UAE) to the northwest, Saudi Arabia to the west, and Yemen to the southwest. The coast is formed by the Arabian Sea on the southeast and the Gulf of Oman on the northeast. The Madha and Musandam enclaves are surrounded by the UAE on their land borders, with the Strait of Hormuz and Gulf of Oman forming Musandam's coastal boundaries.

For a period, Oman was a moderate regional power, formerly having a sultanate extending across the Strait of Hormuz to Iran, and modern day Pakistan, and far south to Zanzibar on the coat of south-east Africa. Over time, as its power declined, the sultanate came under heavy influence from the United Kingdom, though Oman was never formally part of the British Empire, or a British protectorate. The Omani royal family claim that Oman has been ruled by the Al Said dynasty since 1744, although without substantial proof. Oman has long-standing military and political ties with the United Kingdom and the United States, although it maintains an independent foreign policy.