Alanya, formerly Alaiye, is a beach resort city and a district of Antalya Province on the southern coast of Turkey, in the country's Mediterranean Region, 138 kilometres (86 mi) east of the city of Antalya. As of Turkey's 2010 census, the city had a population of 98,627, while the district that includes the city and its built-up region had an area of 1,598.51 km² and 248,286 inhabitants.

Because of its natural strategic position on a small peninsula into the Mediterranean Sea below the Taurus Mountains, Alanya has been a local stronghold for many Mediterranean-based empires, including the Ptolemaic, Seleucid, Roman, Byzantine, and Ottoman Empires. Alanya's greatest political importance came in the Middle Ages, with the Seljuk Sultanate of Rûm under the rule of Alaeddin Kayqubad I, from whom the city derives its name. His building campaign resulted in many of the city's landmarks, such as the Kizil Kule (Red Tower), Tersane (Shipyard), and Alanya Castle.

The Mediterranean climate, natural attractions, and historic heritage make Alanya a popular destination for tourism, and responsible for nine percent of Turkey's tourism sector and thirty percent of foreign purchases of real estate in Turkey. Tourism has risen since 1958 to become the dominant industry in the city, resulting in a corresponding increase in city population. Warm-weather sporting events and cultural festivals take place annually in Alanya.

On the peninsula stands Alanya Castle, a Seljuk era citadel dating from 1226. Most major landmarks in the city are found inside and around the castle. The current castle was built over existing fortifications and served the double purpose of a palace of local government and as a defensive structure in case of attack. In 2007, the city began renovating various sections of the castle area, including adapting a Byzantine church for use as a Christian community center. Inside the castle is the Süleymaniye mosque and caravanserai, built by Suleiman the Magnificent. The old city walls surround much of the eastern peninsula, and can be walked. Inside the walls are numerous historic villas, well preserved examples of the classical period of Ottoman architecture, most built in the early 19th century.

The Kizil Kule (Red Tower) is a 108-foot (33 m) high brick building, standing at the harbor below the castle, and containing the municipal ethnographic museum. Sultan Kayqubad I brought the architect Ebu Ali from Aleppo, Syria to Alanya to design the building. The last of Alanya Castle's 83 towers, the octagonal structure specifically protected the Tersane (dockyard), it remains one of the finest examples of medieval military architecture. The Tersane, a medieval drydock built by the Seljuk Turks in 1221, 187 by 131 feet (57 by 40 m), is divided into five vaulted bays with equilateral pointed arches. The Alara Castle and caravanserai near Manavgat, also built under Kayqubad's authority, has been converted into a museum and heritage center.

Atatürk's House and Museum, from his short stay in the city on February 18, 1935, is preserved in its historic state and is an example of the interior of a traditional Ottoman villa, with artifacts from the 1930s. The house was built between 1880 and 1885 in the "karniyarik" (stuffed eggplant) style. Bright colors and red roofs are often mandated by neighborhood councils, and give the modern town a pastel glow. Housed in a 1967 Republican era building, The Alanya Museum is inland from Damlatas Beach.

Alanya is a member of the Norwich-based European Association of Historic Towns and Regions. In 2009, city officials filed to include Alanya Castle and Tersane as UNESCO World Heritage Sites, and were named to the 2009 Tentative List.