Grand Comore (also known as Grande Comore or Ngasidja) is an island in the Indian Ocean off the coast of Africa. It is the largest island in the Comoros nation. Most of its population is of the Comorian ethnic group. Its population as of 1991 is about 234,000. Its capital is Moroni, which is also the national capital. According to the constitution of 2002, it is governed by an elected President, as are the other islands, with the federal government being much reduced in power.

For several centuries, Grande Comore was divided into more than a dozen sultanates, including Bambao, Itsandra, Mitsamihuli, Bajini, Hambu, Washili, Hamahame, Mbude, Hamvu and LaDombe. The sultans were also known as falmes. In 1886 the ruler of Bambao, Saidi Ali ibn Saidi Omar, united the sultanates of Grand Comore into the state of Ngasidja, with the other sultanates maintaining autonomy. That same year, France established a protectorate over the island. In 1893 Saidi Ali went into exile. In 1911 France annexed the island and the sultanates were abolished. In 1975 Grand Comore federated with Anjouan and Moheli to from the nation of Comoros. In 1997 the Comoros nation began to fall apart as Anjouan and Moheli seceeded. Grand Comore became the only island under federal control. By 2002, however, Grand Comore was reunited with the other islands under the new constitution.