Tihamah or Tihama (Arabic: تهامة‎ Tihāmah) is a narrow coastal region of Arabia on the Red Sea. It is currently divided between Saudi Arabia and Yemen. In a broad sense, Tihamah refers to the entire coastline from the Gulf of Aqaba to the Bab el Mandeb Strait but it more often refers only to its southern half, starting just south of Jeddah and running parallel to Asir and Yemen. Unlike the inland regions, it is made up of sand dunes and plains and is largely arid except for a few oases. Important urban centers of the region include Al Hudaydah, Mocha, and Zabid in Yemen and Jizan, Al-Qunfudhah, Bareg, and Al Lith in Saudi Arabia. Most of the Tihama coastline is hazardous to approaching vessels, and harbors are therefore few and far between, especially in the northern half.

In modern times, Tihama has come to be viewed as made up of three sections, each named after the inland region adjacent to it. The northern section, therefore, is known as Tihamat al-Hejaz, the middle section as Tihamat 'Asir, and the southern section as Tihamat al-Yemen. The middle and southern sections are part of the Arabian Peninsula coastal fog desert ecoregion.