"I know for certain that Chris would not have wanted his name or memory used in that connection," Mary Commanday wrote in a short letter to the editor of The New York Times, which was published yesterday.
"I hope that there will be an immediate and permanent stop to this opportunistic and cynical use by the campaign," she said.
The Benghazi attack took place on September 11, 2012, when Islamic militants attacked the American diplomatic compound, killing Ambassador Stevens and US Foreign Service Information Management Officer Sean Smith.
The Benghazi attacks were frequently mentioned in speeches at last week's Republican National Convention in Cleveland, where speakers used it as a reason presumptive Democratic nominee Hillary Clinton is unfit for the presidency, CNN reported.
Clinton was secretary of state at the time of the attacks. Some conservatives blame Clinton and the Obama administration for security failures in Benghazi that they blame for the deaths of Stevens and three other Americans.