Gregory Alan Ballard (born November 20, 1954) is an American politician, author, and businessman who served as the 48th mayor of Indianapolis, Indiana.
He is a retired Lieutenant Colonel from the United States Marine Corps.
On Tuesday, November 6, 2007, he defeated two-term incumbent Democratic Mayor Bart Peterson by 51% to 47%.
It was described as one of the biggest upsets in the political history of Indiana.
He was re-elected to the position in November 2011, by the same margin.