Rudolph Romeo Riddell (11 February 1847 – 8 September 1913) was a Lieutenant in the United States Army who was awarded the Medal of Honor for gallantry during the American Civil War.

On 6 April 1865, during the Battle of Sailor's Creek near Farmville, Virginia, he captured the flag of the 6th Alabama Cavalry of the Confederate Army.

[4][5][6] Riddell's Medal of Honor citation reads:[2] The President of the United States of America, in the name of Congress, takes pleasure in presenting the Medal of Honor to Lieutenant Rudolph R. Riddell, United States Army, for extraordinary heroism on 6 April 1865, while serving with Company I, 61st New York Infantry, in action at Deatonsville (Sailor's Creek), Virginia.

He later served as the Chief of the Bureau of Information and Statistics, New York State Department of Agriculture.

[6] He was a Freemason and one of the founders of the Mystic Order of Veiled Prophets of the Enchanted Realm ("Grotto") and the author of its ritual.