Daegu ([tɛ̝.ɡu], Korean: 대구; Hanja: 大邱; lit. large hill), formerly spelled Taegu and officially known as the Daegu Metropolitan City (Korean: 대구광역시; Hanja: 大邱廣域市), is a city in South Korea.

It is the third-largest urban agglomeration in South Korea after Seoul and Busan; it is the third-largest official metropolitan area in the nation with over 2.5 million residents; and the second-largest city after Busan in the Yeongnam region in southeastern Korean Peninsula. Daegu and surrounding North Gyeongsang Province are often referred to as Daegu-Gyeongbuk, with a total population over 5 million.

Daegu is located in south-eastern Korea about 80 km (50 mi) from the seacoast, near the Geumho River and its mainstream, Nakdong River in Gyeongsang-do. The Daegu basin is the central plain of the Yeongnam region. In ancient times, the Daegu area was part of the proto-kingdom Jinhan. Subsequently, Daegu came under the control of the Silla Kingdom, which unified the Korean Peninsula. During the Joseon Dynasty period, the city was the capital of Gyeongsang-do, one of the traditional eight provinces of the country.

Daegu was an economic motor of Korea during the 1960s–1980s period and was especially known for its electronics industry. The humid subtropical climate of Daegu is ideal for producing high-quality apples, thus the nickname, "Apple City". Daegu is also known as "Textile City". Textiles used to be the pillar industry of the city. With the establishment of the Daegu-Gyeongbuk Free Economic Zone, Daegu is currently focusing on fostering fashion and high-tech industries.

Daegu was the host city of the 22nd World Energy Congress, the 2011 World Championships in Athletics and the 2003 Summer Universiade. It also hosted four matches in the 2002 FIFA World Cup.