Grenville Gaines (September 26, 1854 – May 2, 1922) was an American politician, lawyer and banker from Virginia.

His grandfather James Foster was a planter in Prince William County and a Virginia state politician.

He attended Virginia Military Institute from 1870 to 1874 and graduated in the class of 1874 as a civil engineer.

[2][3][4] He was a member of the board of commissioners for the eighth district of Virginia for the World's Columbian Exposition in 1893.

He was elected colonel of the Third Virginia Regiment of the National Guard on March 12, 1898.