Greater Tunb and Lesser Tunb are two small islands in the eastern Persian Gulf, close to the Strait of Hormuz. They lie at some 12 kilometers from each other and 20 kilometers south of the Iranian island of Gheshm. The islands are administered by Iran as part of its province of Hormozgan, but are also claimed by UAE as a territory of the Emirate of Ras al-Khaimah.
Greater Tunb has a surface of 10.3 km². It is known for its red soil. There are conflicting descriptions about its population: While some sources state there are between a few dozen and a few hundred inhabitants, others describe the island as having no native civilian population. There is reported to be an Iranian garrison and naval station, a fish storage facility and a red-soil mine.
Lesser Tunb has a surface of 2 km² and is uninhabited with the exception of a small airfield, harbor, and entrenched Iranian military unit. The toponymy of Tonb is in all likelihood of Persian origin. In the local Persian dialect(s) of southern Persia, the noun tonb, with its diminutive tonbu, as it applied to Lesser Tonb, means "hill" or "low elevation" . The terms have the same meaning in the larger Dari Persian language system; this explains in part the traces of tonb and tonbu in the toponyms found in the Bushehr and Lengeh regions, some 300 miles (480 km) apart.