Sunjo, personal name Yi Gong, was the 23rd monarch of the Joseon dynasty of Korea. He was the second son of King Jeongjo by his concubine, Royal Noble Consort Su of the Bannam Park clan.

Joseon, officially Great Joseon State, was a dynastic kingdom of Korea that lasted just over 500 years. It was founded by Taejo of Joseon in July 1392 and replaced by the Korean Empire in October 1897. The kingdom was founded following the aftermath of the overthrow of Goryeo in what is today the city of Kaesong. Early on, Korea was retitled and the capital was relocated to modern-day Seoul. The kingdom's northernmost borders were expanded to the natural boundaries at the rivers of Amnok and Tuman through the subjugation of the Jurchens.