Sullivan's Island, South Carolina is an American town in Charleston County, South Carolina, at the entrance to Charleston Harbor, with a population was 1,911 at the 2000 United States Census. According to the U.S. Census Bureau, the town has a total area of 3.3 square miles, of which, 2.4 square miles of it is land and 0.9 square milesof it (27.11%) is water. The Ben Sawyer Bridge connects Sullivan's Island to Mount Pleasant, South Carolina. A bridge spanning Breach Inlet connects it to Isle of Palms, South Carolina.

Sullivan's Island was the site of a major battle of the American Revolution at Fort Sullivan (now Fort Moultrie) on June 28, 1776. Sullivan's Island was also the point of entry for approximately 40 percent of the enslaved Africans brought to British North America, and has been likened to Ellis Island in New York City, New York. On September 23, 1989, Hurricane Hugo came ashore near Sullivan's Island; few people were prepared for the destruction that followed in its wake. The eye of the hurricane passed directly over Sullivan's Island. The Ben Sawyer Bridge was a casualty of the hurricane. The swing bridge broke free of its locks, and before the storm was over, one end of the bridge was in the water and the other was pointing skyward. Sullivan's Island police chief, Jack Lilien, was the last person to leave the island before the bridge gave way.

As defined by the U.S. Office of Management and Budget, and used by the U.S. Census Bureau for statistical purposes only, Sullivan's Island is included within the Charleston-North Charleston-Summerville metropolitan area and the Charleston-North Charleston Urbanized Area.