Galdor was an elf of Gondolin, deemed the most valiant of the Gondolindrim, with the exception of Turgon himself.

He was the Lord of the Folk of the Tree and hence called "Galdor of the Tree". The folk of the tree fought with iron-studded clubs or slings and their garment was green.

During the siege of Gondolin, Galdor saved Tuor when he fell carrying the wounded Ecthelion of the Fountain. Tuor would have been killed by orcs if Galdor hadn't interfered. He escaped together with Tuor and others and came to the mouth of Sirion. He survived the onslaught of Maedhros, Maglor, Amrod and Amras and was rescued by Círdan and Gil-Galad.

He was possibly the same elf who came to Rivendell before the War of the Ring, sent by Círdan from the Grey Havens.