Balhae (Korean: 발해; Korean pronunciation: [pa̠ɽɦɛ̝], Chinese: 渤海; pinyin: Bóhǎi, Russian: Бохай, romanized: Bokhay, Manchu: ᡦᡠᡥᠠ‍ᡳ), also rendered as Bohai, was a multi-ethnic kingdom whose land extends to what is today Northeast China, the Korean Peninsula and the Russian Far East. It was established in 698 by Dae Joyeong (Da Zuorong) and originally known as the Kingdom of Jin (Zhen) until 713 when its name was changed to Balhae.

Balhae's early history involved a rocky relationship with the Tang dynasty that saw military and political conflict, but by the end of the 8th century the relationship had become cordial and friendly. The Tang dynasty would eventually recognize Balhae as the "Prosperous Country of the East". Numerous cultural and political exchanges were made. Balhae was conquered by the Khitan-led Liao dynasty in 926. Balhae survived as a distinct population group for another three centuries in the Liao and Jin dynasties before disappearing under Mongol rule.

The history surrounding the origin of the state, its ethnic composition, the modern cultural affiliation of the ruling dynasty, the reading of their names, and its borders are the subject of a historiographical dispute between Korea, China and Russia. Historical sources from both China and Korea have described Balhae's founder, Dae Joyeong, as related to the Mohe people and Goguryeo.