In the works of J. R. R. Tolkien, the Noldor (also spelled Ñoldor, meaning those with knowledge in his constructed language Quenya) are a kindred of Elves who migrate west to the blessed realm of Valinor from the continent of Middle-earth, splitting from other groups of Elves as they went. They then settle in the coastal region of Eldamar. The Dark Lord Morgoth murders their first leader, Finwë. The majority of the Noldor, led by Finwë's eldest son Fëanor, then return to Beleriand in the northwest of Middle-earth. This makes them the only group to return and then play a major role in Middle-earth's history; much of The Silmarillion is about their actions. They are the second clan of the Elves in both order and size, the other clans being the Vanyar and the Teleri.

Among Elves, the Noldor show the greatest talents for intellectual pursuits, technical skills and physical strength, yet are prone to unchecked ambition and pride in their ability to create. Scholars such as Tom Shippey have commented that these attributes lead to their decline and fall, especially through Fëanor who creates and covets the magical jewels, the Silmarils. Others including Dimitra Fimi have linked the Noldor to the mythical Irish warriors and sorcerers, the Tuatha Dé Danann.