Herennia Cupressenia Etruscilla was Roman empress as the wife of Emperor Decius. She was the mother of Emperors Herennius Etruscus and Hostilian.
As with most third-century Roman empresses, very little is known about her. The date and place of her birth are not known for certain. She was probably from a senatorial family of Herennia gens. Itis assumed that her ancestors settled in Etrurian lands. Herennia married Decius probably before 230 therefore, Herennia was born in early 3rd century AD. She gained the title Augusta when Decius became emperor in 249 AD. After the death of both Decius and Herennius Etruscus in the Battle of Abritus, Trebonianus Gallus, the governor of Moesia, was elected as emperor in June 251 AD.
In order to gain popular support, Trebonianus Gallus retained Herennia Etruscilla as Augusta (empress-mother) and elevated Hostilian to Augustus, making him co-emperor alongside Trebonianus Gallus himself. Hostilian died in July 251, either from a plague or murder,  after which Trebonianus Gallus' son Volusianus, was raised to Augustus. In November 251 AD, Herennia survived the epidemic, in which her son Hostilian died, retained the role of Augusta, despite any familial ties to Gallus and lived until 253 AD, corresponding to the end of his reign.