William Jasper (circa 1750 – October 9, 1779) was a sergeant in the 2nd South Carolina Regiment.

Jasper distinguished himself in the defense of Fort Moultrie (then called Fort Sullivan) on June 28, 1776. When a shell from a British warship shot away the flagstaff, he recovered the South Carolina flag in the Battle of Sullivan's Island, raised it on a temporary staff, and held it under fire until a new staff was installed.

At the Siege of Savannah, he received his death wound while fastening to the parapet the standard which had been presented to his regiment. His hold, however, never relaxed, and he bore the colors to a place of safety before he died.

Later, his exploits were exaggerated by Parson Weems.