USNS Mercy (T-AH-19) is the lead ship of her class of hospital ships in non-commissioned service with the United States Navy. Her sister ship is USNS Comfort (T-AH-20). She is the third US Navy ship to be named for the virtue mercy. In accordance with the Geneva Conventions, Mercy and her crew do not carry any offensive weapons, though defensive weapons are available.

The Mercy class of hospital ships are converted San Clemente-class supertankers used by the United States Navy. Originally built in the 1970s by the National Steel and Shipbuilding Company, they were acquired by the Navy and converted into hospital ships, coming into service in 1986 and 1987.