The leafy seadragon (Phycodurus eques) or Glauert's seadragon, is the only member of the genus Phycodurus and is a marine fish in the family Syngnathidae, which includes seadragons, pipefish, and seahorses.

It is found along the southern and western coasts of Australia. The name is derived from the appearance, with long leaf-like protrusions coming from all over the body. These protrusions are not used for propulsion; they serve only as camouflage. The leafy seadragon propels itself by means of a pectoral fin on the ridge of its neck and a dorsal fin on its back closer to the tail end. These small fins are almost completely transparent and difficult to see as they undulate minutely to move the creature sedately through the water, completing the illusion of floating seaweed.

Popularly known as "leafies", it is the marine emblem of the state of South Australia and a focus for local marine conservation.