Samuel Dana Greene Sr. (February 11, 1839 – December 11, 1884) was an officer in the United States Navy during the American Civil War, mostly noted for his service aboard the USS Monitor during the Battle of Hampton Roads.

He entered the United States Naval Academy on September 21, 1855, and graduated on June 9, 1859, with the rank of midshipman.

During the battle he assumed full command of Monitor when Worden was temporarily blinded by shell fragments from an explosion from one of Virginia's broadsides.

After the subsequent retreat and assessment of all damage Greene ordered the return to battle and continued engaging the Virginia to a standoff.

[5] He served as the head of the department of astronomy, navigation and surveying at the Naval Academy from 1871 to 1875,[6] receiving promotion to Commander on December 12, 1872.