Queen Jeongseong (Korean: 정성왕후 서씨; 2 January 1693 – 23 March 1757), of the Daegu Seo clan, was the first wife of King Yeongjo of Joseon and the adoptive mother of Crown Prince Sado.

Prince Yeoning ascended the throne on 30 August of that year as King Yeongjo and she became his queen consort.

The Queen died at Changdeok Palace on 3 April 1757, and is buried in Seoreung within Hongreung in Yongdu-gong, Deokyang ward, Goyang, Gyeonggi Province.

But because her tomb was built before her husband died, King Yeongjo reserved a spot next her mound intending to be buried with her.

As well as the death of her legal mother-in-law, Queen Dowager Hyesun, who died one month later on 2 May 1757 which contributed to the Crown Prince’s declining mental condition.