HMS Serapis was a Royal Navy two-decked, Roebuck-class fifth rate. Randall & Brent built her at Greenland South Dockyard, Rotherhithe and launched her in 1779. She was armed with 44 guns (twenty 18-pounders, twenty 9-pounders, and four 6-pounders). Serapis was named after the god Serapis in Greek and Egyptian mythology. The Americans captured her during the American Revolutionary War. They transferred her to the French, who commissioned her as a privateer. She was lost off Madagascar in 1781 to a fire.