The Sultanate of Yogyakarta, officially the Sultanate of Ngayogyakarta Hadiningrat (Javanese: ꦏꦱꦸꦭ꧀ꦠꦤ꧀ꦤꦤ꧀​ꦔꦪꦺꦴꦒꦾꦏꦂꦡ​ꦲꦢꦶꦤꦶꦔꦿꦠ꧀, romanized: Kasultanan Ngayogyakarta Hadiningrat Javanese pronunciation: [ŋajogjɔkartɔ hadinɪŋrat]; Indonesian: Kesultanan Yogyakarta), is a Javanese monarchy in Yogyakarta Special Region, in the Republic of Indonesia. The current head of the sultanate is Hamengkubuwono X.

Yogyakarta existed as a state since 1755 on the territory of modern Indonesia in the central part of Java Island. The sultanate became the main theatre of military operations during the Java War of 1825–1830, following which a significant part of its territory was annexed by the Dutch, and the degree of autonomy was significantly curtailed. In 1946–1948, during The Indonesian war of independence, the capital of the republic was transferred to the territory of the sultanate, in the city of Yogyakarta.

In 1950, Yogyakarta, along with the Principality of Pakualaman, became part of Indonesia, with the former royal realms united as a Special Region, with status equal to that of a national province. At the same time, the hereditary titles of Sultan of Yogyakarta and Prince of Pakualaman, with ceremonial privileges carried with the titles, were legally secured for the rulers. In 2012, the Indonesian government secured Act No. 13 of 2012 which formally recognised the reigning sultan of Yogyakarta as the hereditary governor of the Special Region of Yogyakarta, with the Pakualam Prince as its hereditary vice-governor (article 18, paragraph 1c). That act also formally incorporated the sultanate as a corporation sole with the privilege of land ownership, therefore restoring the sultanate's right to own crown land (which it originally rescinded in the 1980s); as of 2019, the sultanate is claimed to own almost 10% of land in the Special Region of Yogyakarta.

The sultanate is located on the southern coast of the island of Java. In the south, it is bordered by the Indian Ocean, with land surrounded by the province of Central Java. The area is 3,133 km², while the population in 2010 was about 3.5 million people. The special district of Yogyakarta, along with Jakarta, has the largest population density among the provinces of Indonesia.

Not far from the city of Yogyakarta is the volcano Merapi, the most active volcano in Indonesia which has erupted regularly since 1548, resulting in great damage to the population of the district. In October–November 2010, there was a strong volcanic eruption, forcing about a 100,000 people to temporarily leave their homes.

After the death of Sultan Agung in 1645, the Sultanate of Mataram went into decline due to a power struggle within the sultanate itself. The Dutch East India Company also exploited the power struggle to increase its control. At the peak of the conflict, the Mataram Sultanate was split into two based on the Treaty of Giyanti of 13 February 1755: Yogyakarta Sultanate and Surakarta Sunanate.

The Giyanti Treaty mentioned Pangeran Mangkubumi as Sultan of Yogyakarta with the title of

ꦔꦂꦱꦢꦊꦩ꧀ꦱꦩ꧀ꦥꦺꦪꦤ꧀ꦢꦊꦩ꧀ꦲꦶꦁꦏꦁꦱꦶꦤꦸꦮꦸꦤꦏꦁꦗꦼꦁꦱꦸꦭ꧀ꦠꦤ꧀ꦲꦩꦼꦁꦏꦸꦨꦸꦮꦤꦱꦺꦤꦥꦠꦶꦲꦶꦁꦔꦭꦒꦔꦧ꧀ꦢꦸꦭ꧀ꦫꦏ꦳꧀ꦩꦤ꧀ꦱꦪꦶꦢꦶꦤ꧀ꦥꦤꦠꦒꦩꦏ꦳ꦭꦶꦥ꦳ꦠꦸꦭ꧀ꦭꦃ Ngarsa Dalem Sampeyan Dalem Ingkang Sinuwun Kangjeng Sultan Hamengkubuwana Senopati-ing-Ngalaga Ngabdulrakhman Sayyidin Panatagama Khalifatullah