The Letoon (Ancient Greek: Λητῶον), sometimes Latinized as Letoum, was a sanctuary of Leto near the ancient city Xanthos in Lycia. It was one of the most important religious centres in the region. The site is located south of the village Kumluova in the Fethiye district of Antalya Province, Turkey. It lies approximately four kilometres south of Xanthos along the Xanthos River.