Treebeard or (Sindarin) Fangorn is a fictional character from J. R. R. Tolkien's Middle-earth. He is the oldest of the Ents, a tree-like being who is a sort of "shepherd of trees". Very tall and stiff-limbed, with bark-like skin and leafy hair, he befriends Meriadoc Brandybuck and Peregrin Took after they escape from Orcs. He leads a troop of Ents to destroy Saruman's fortress, Isengard. He lives in Fangorn forest, which is named after him (or he after it).

Like most ents, Treebeard takes a long time to make up his mind. He repeatedly speaks of not "being hasty". But he makes a momentous decision about the orcs, Saruman and Orthanc after hearing the hobbits' report.

Treebeard is described as the oldest being in Middle-earth, which is the cause of some confusion as Tom Bombadil is also called oldest. Treebeard however says that there are trees in Fangorn that are 'older than he'. The general consensus is that Treebeard is the oldest "living thing" in Middle-earth, as Tom Bombadil isn't exactly member of any race.

In the film, The Lord of the Rings: The Two Towers, Treebeard is a combination of a large animatronic model and a CGI construct; his voice is performed by John Rhys-Davies, who also plays Gimli.