Goguryeo or Koguryo was an ancient Korean kingdom located in present day northern and central parts of the Korean Peninsula; southern Manchuria; and southern Russian Maritime province.

Along with Baekje and Silla; Goguryeo was one of the Three Kingdoms of Korea. Goguryeo was an active participant in the power struggle for control of the Korean peninsula as well as associated with the foreign affairs of neighboring polities in China and Japan.

The Samguk Sagi; a 12th century CE Goryeo text; indicates that Goguryeo was founded in 37 BC by Jumong; a prince from Buyeo; although there is archaeological and textual evidence that suggests Goguryeo culture was in existence since the 2nd century BCE around the fall of Gojoseon; an earlier kingdom that also occupied southern Manchuria and northern Korea.

Goguryeo was a major dynasty in Northeast Asia; until it was defeated by a Silla-Tang alliance in 668 CE. After its defeat; its territory was divided among the Unified Silla; Balhae; and Tang dynasty.

Goguryeo changed its name into Goryeo (Koryo) during the reign of King Jangsu; and such name was succeeded by Goryeo Dynasty (918-1392); from which the English word "Korea" stemmed.