Ralph Elliott Robertson (October 18, 1885 – February 28, 1961), more commonly known as R. E. "Bob" Robertson, was an American lawyer and politician from the territory and state of Alaska. He was a member of the Republican Party. Born in Sioux City, Iowa, Robertson was educated at Omaha Commercial College, the Michigan College of Mines and the University of Washington. He moved to Alaska in 1906 and served as mayor of Juneau from 1920 to 1923. He also served as a trustee of the Alaska Agricultural College and School of Mines, from 1925 to 1933.