Denise Cosby filed the wrongful death lawsuit in Middlesex Superior Court last week, the Boston Globe reported Wednesday.
The mother alleges the university and its officials failed to protect her son, Justin Cosby, 21, who was shot inside Kirkland Hall May 18, 2009, in a drug robbery by Jabrai Jordan Copney and two other people.
Neither Cosby nor Copney were Harvard students.
"She feels that it's the university's fault," Denise Cosby's attorneys, Issac H. Peres, said. "But for their negligence in allowing this murderer to live and operate a criminal enterprise on campus, her son would be alive today."
Harvard spokesman Kevin Galvin said, "We recognize that the Cosby family has suffered a heart-rending loss, but there is no basis in law or fact to hold the university accountable for Justin Cosby's death."
Cosby "entered Harvard property that day for the sole purpose of selling a large quantity of marijuana to people unaffiliated with the University and one of them shot him," Galvin said in a statement. "We will vigorously defend against this lawsuit."