Benjamin Jeffery Sweet (April 24, 1832 – January 1, 1874) was an American lawyer, politician, public administrator, and Union Army officer.

His two daughters, Ada Celeste Sweet and Winifred Bonfils were also important figures in the history of the battle for women's rights.

Soon after the outbreak of the American Civil War, on July 16, 1861, Sweet joined the 6th Wisconsin Volunteer Infantry Regiment of the Union Army and was given the rank of major.

[2] Following recuperation from his injury, Sweet was given command of Camp Douglas after Brigadier General William W. Orme resigned on May 2, 1864.

This notwithstanding, Sweet would soon be lauded for "discovering" and "thwarting" a bogus plot by spies for the Confederacy to liberate Confederate prisoners of war and attack Chicago on the eve of the 1864 United States presidential election.