The Carolina Marsh Tacky or Marsh Tacky is a rare breed of horse, native to South Carolina. It is a member of the Colonial Spanish group of horse breeds, which also include the Florida Cracker Horse and the Banker horse of North Carolina. It is a small horse, well adapted for use in the lowland swamps of its native South Carolina. The Marsh Tacky developed from Spanish horses brought to the South Carolina coast by Spanish explorers, settlers and traders as early as the 16th century. The horses were used by the colonists during the American Revolution, and by South Carolinians for farm work, herding cattle and hunting throughout the breed's history.
The breed is considered to be critically endangered by both the American Livestock Breeds Conservancy and the Equus Survival Trust, and there are thought to be less than 150 Marsh Tackies in existence today.