Tidore is a city, island, and archipelago in the Maluku Islands of eastern Indonesia, west of the larger island of Halmahera. In the pre-colonial era, the kingdom of Tidore was a major regional political and economic power, and a fierce rival of nearby Ternate, just to the north.

Tidor Island consists of a large stratovolcano which rises from the seafloor to an elevation of 1,730 m (5,676 ft) above sea level at the conical Kiematabu Peak on the south end of the island. The northern side of the island contains a caldera, Sabale, with two smaller volcanic cones within it.

Soasio is Tidore's capital. It has its own port, Goto, and it lies on the eastern edge of the island. It has a mini bus terminal and a market. The sultan's palace was rebuilt with completion in 2010.

Tidore was a spice-funded sultanate that was founded in 1109, and spent much of its history in the shadow of Ternate, another sultanate.

The sultans of Tidore ruled most of southern Halmahera, and, at times, controlled Buru, Ambon and many of the islands off the coast of New Guinea. Tidore established an alliance with the Spanish in the sixteenth century, and Spain had several forts on the island. There was mutual distrust between the Tidorese and the Spaniards but for the Tidorese the Spanish presence was helpful in resisting the incursions of the Ternateans and their ally, the Dutch, who had a fort on Ternate. For the Spanish, backing the Tidore state helped check the expansion of Dutch power that threatened their nearby Asia-Pacific interests, provided a useful base right next to the centre of Dutch power in the region and was a source of spices for trade.