The Gugyedong Formation (Korean: 구계동층; Hanja: 龜溪洞層; RR: Gugyedong-cheung), also known as the Guyedong Beds, is an Aptian to Albian geologic formation in South Korea.

[1] Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.

[2] The following fossils have been reported from the formation:[1]