In J. R. R. Tolkien's fictional world of Middle-earth, Thingol was the Sindarin form of the surname of one of the kings of the Teleri. (The Quenya form of the same name is 'Elwë Singollo,' 'Singollo' meaning 'Greycloak.')
The first mention of Thingol is when he travels from Cuivienen with Oromë to see the land of Valinor. Upon his return, he manages to convince many of his people to follow him back to that country. On the Great Journey to Beleriand, the Teleri lag behind, and do not arrive at the coast until after the departure of the moving island of Tol Eresseä. Thus, they stay in Beleriand for many years until Tol Eresseä is brought again to fetch them. By this time, many of the Teleri have grown to like Beleriand, and decide to stay there. Elwë is among them, having encountered Melian the Maia in the woods of Nan Elmoth and fallen deeply in love with her. Thingol and Melian become king and queen of the Teleri who stay in Beleriand, now called the Sindar. (Neither Thingol nor Melian are counted among the Sindar, however, since Melian is not an Elf, and Thingol has seen the light of the Two Trees of Valinor.) Melian has a daughter, named Lúthien and said to be the fairest woman ever to live.
Lúthien fell in love with a Man named Beren. Thingol did not wish for the two to wed, as he thought the world of his daughter, but disliked Men. As a bride-price he asked for a Silmaril from the crown of Morgoth. It was, however, this very bride-price that killed him. Thingol became obsessed with the Silmaril and hired some Dwarves to place it in the Nauglamír, the Necklace of the Dwarves. The Dwarven craftsmen also became obssessed with the jewel and slew Thingol for possession of it, setting off a chain of events that led to the destruction of Doriath and the scattering of its people.