Nine Muses A (, stylized in all caps or 9MUSES AMUSE) was the first sub-group of South Korean girl group Nine Muses formed by Star Empire Entertainment in 2016. It is composed of four Nine Muses members: Gyeongree, Hyemi, Sojin and Keumjo. The group released their debut single album Muses Diary on August 4, 2016.
After the departure of members Minha and Euaerin from Nine Muses in June 2016, Star Empire announced that the group would be making a summer comeback with a unit promotion with no further details. In early July, it was officially announced that the sub-unit would consist of four members, revealing member Gyeongree as the first official member of the sub-unit. The sub-unit debuted in early August. On July 21, it was revealed that the full line-up for the sub-group consisted of members Gyeongree (Center), Hyemi (Leader), Sojin (Rapper) and Keumjo (Main Vocal), also revealing that the song "Lip 2 Lip" would be their debut song. Nine Muses A is a shortened name for Nine Muses Amuse, meaning that the group will always make others happy and let them have a great time with their performance.
Nine Muses A released their debut single album Muses Diary on August 4, 2016.
On March 21, 2023, it was announced that Nine Muses A would be releasing a song in May, followed by a full group comeback sometime in July or August, though the line-up for the full group comeback has yet to be confirmed.