Robert Donati (June 4, 1940 – c. September 21, 1991), who went by the name of Bobby and was also known by the nickname Bobby D – was an American career criminal. Along with his twin brother Richard, he was associated with the New England-based Patriarca crime family. His criminal history dates to 1958, when he was 17. He and his brothers were long believed to be part of the Angiulo Brothers' crew, with whom they carried out burglaries.

On September 24, 1991 – three days after he had last been seen alive leaving his house in the Boston suburb of Revere – his bound, beaten, and stabbed body was found in the trunk of his Cadillac, a short distance away. The killing remains unsolved.

Donati's death has long been attributed to the struggle between two factions for control of the Patriarca family at that time, after Raymond Patriarca, Jr. proved unable to unite the family following his father's death. Donati was reportedly a government informant, although federal prosecutors have denied it.

In recent years, however, Donati has been identified as possibly being involved in the 1990 theft of art worth $500 million from Boston's Isabella Stewart Gardner Museum, the largest art theft ever. Some accounts link his death to that crime instead. It has been reported that Donati stole the art in an attempt to get his boss Vincent M. Ferrara released from jail in order to ensure Ferrara would not be killed by the rival faction, which was gaining control of the Patriarca family at that time. The Federal Bureau of Investigation (FBI), which had Donati under heavy surveillance at the time of his death, has not publicly identified him as a suspect in the art theft, which it is still investigating.