Robert Donald Blue (September 24, 1898 – December 14, 1989) was an American politician, the 30th Governor of Iowa from 1945 to 1949.

Blue attended Capital City Commercial College and Iowa State University.

One of his principal opponents in the legislature, William S. Beardsley, took advantage of Blue's unpopularity and successfully challenged him in the Republican primary in 1948.

Blue left public life and returned to his hometown of Eagle Grove.

He died of a stroke in Fort Dodge, Iowa on December 14, 1989.