Sermersooq is a municipality in Greenland, formed on 1 January 2009 from five earlier, smaller municipalities. Its administrative seat is the city of Nuuk, the capital of Greenland, and it is the most populous municipality in the country, with 23,123 inhabitants as of January 2020.

Nuuk is the capital of and most populous city in Greenland, an autonomous territory in the Kingdom of Denmark. Nuuk is the seat of government and the territory's largest cultural and economic center. The major cities from other countries closest to the capital are Iqaluit and St. John's in Canada and Reykjavík in Iceland. Nuuk contains a third of Greenland's population and its tallest building. Nuuk is also the seat of government for the Sermersooq municipality. In January 2023, it had a population of 19,604. Nuuk is considered a modernized city after the policy began in 1950.