George Sears "Pop" Greene (May 6, 1801 – January 28, 1899) was a civil engineer and a Union general during the American Civil War. He was part of the Greene family of Rhode Island, which had a distinguished military record for the United States. His greatest contribution during the war was his defense of the Union right flank at Culp's Hill during the Battle of Gettysburg. As a civilian, he was a founder of the American Society of Civil Engineers and Architects and was responsible for numerous railroads and aqueduct construction projects in the northeastern United States.