19th king of Goguryeo (r. 391–412); conquering monarch who greatly expanded its territory

| Life | 374 ~ 412 |
| Era | 고구려(삼국시대) |
| Clan | 고구려 왕실 |
King Gwanggaeto the Great was the 19th monarch of Goguryeo, personal name Damdeok, with the posthumous title Gukgangsang Gwanggaetogyeong Pyeongan Hotae-wang. He ascended the throne in 391 at age 18 and adopted the independent era name Yeongnak.
During his reign he pressured Baekje and seized numerous fortresses north of the Han River, repelled Wa and Gaya forces at Silla's request, and campaigned north against the Khitan and Later Yan, extending Goguryeo's power across much of Manchuria and making it a major East Asian power.
After his death, his son King Jangsu erected the Gwanggaeto Stele at the Goguryeo capital of Gungnae (present-day Ji'an, Jilin Province, China), which records his achievements in detail and remains a key epigraphic source for the history of 4th–5th century Goguryeo and ancient Korea-Japan relations. The Goguryeo royal house bore the surname Go, but no verified genealogical line connects it to any present-day Korean clan seat.
Royal tomb in the Ji'an area, Jilin Province, China (identified by some scholars as Taewangneung or the General's Tomb; the attribution is debated)