The Saudi Arabia–Yemen border is 1,307 km (812 mi) in length and runs from the Red Sea coast in the west to the tripoint with Oman in the east.

Historically there was no clearly defined boundary in this part of the Arabian Peninsula; at the start of the 20th century the Ottoman Empire controlled the western coast as far south as North Yemen, Britain controlled Aden (South Yemen), with the interior consisting of loosely organised Arab groupings, occasionally forming emirates, the most prominent of which was the Emirate of Nejd and Hasa ruled by the al-Saud family.

[6] By the Treaty of Taif, signed 12 May 1934, a partial border was drawn that extended inland to the vicinity of Najran, being demarcated on the ground in the following two years.

[7][4] On 25 November 1935 British officials met with Ibn Saud in an attempt to finalise a frontier between the new kingdom and Britain's Arabian protectorates, including Aden colony.

[4] Following the unification of Yemen in 1990, the upcoming need to renew the Treaty of Taif, and also the discovery of oil in the border region, prompted the reinstigation of boundary negotiations in 1992.