Fingolfin (Sindarin: [fiŋˈɡolfin]) is a character in J. R. R. Tolkien's legendarium, appearing in The Silmarillion. He was the son of Finwë, High King of the Noldor. He was threatened by his half-brother Fëanor, who held him in contempt for not being a pure-bred Noldor. Even so, when Fëanor stole ships and left Aman, Fingolfin chose to follow him back to Middle-earth, taking the dangerous route over the ice of the Helcaraxë. On arrival, he challenged the Dark Lord Morgoth at the gates of his fortress, Angband, but Morgoth stayed inside. When his son Fingon rescued Maedhros, son of Fëanor, Maedhros gratefully renounced his claim to kingship, and Fingolfin became High King of the Noldor. He was victorious at the battle of Dagor Aglareb, and there was peace for some 400 years until Morgoth broke out and destroyed Beleriand in the Dagor Bragollach. Fingolfin, receiving false news, rode alone to Angband and challenged Morgoth to single combat. He wounded Morgoth several times, but grew weary and was killed by the immortal Vala.

Fingolfin has inspired artists, musicians and video game designers to create depictions of his deeds.

Fingolfin was the second son of Finwë, High King of the Noldor, a division of the Elves lower than the Vanyar but higher than the Teleri. He was full brother of Finarfin, and half-brother of Fëanor, who was the eldest of Finwë's sons. He founded the House of Fingolfin which ruled the Noldor in Middle-earth. His wife was Anairë and his children were Fingon, Turgon, Aredhel and Argon. Fingolfin was said to be the strongest, most steadfast, and most valiant of Finwë's sons. His father-name in Quenya—one of Tolkien's fictional languages—was Nolofinwë, or "wise Finwë," while his mother-name was Aracáno, or "High Chieftain", the same name as his youngest son Argon.

The mother of Fingolfin and Finarfin was Finwë's second wife, Indis, who he married after Míriel died. While they lived in Aman, there was always strife between the sons of Indis and Míriel's son Fëanor, mostly due to Melkor's treachery. However, Fingolfin would seek to forge a better relationship with Fëanor at every chance. Even after Fëanor threatened him with a sword and was banished from Tirion, Fingolfin forgave him and tried to mend their relationship. This occurred very soon before destruction of the Two Trees and the Darkening of Valinor. After this event and Fëanor's decision to leave Aman, Fingolfin chose to follow him into exile, so as not to abandon his people.

Fingolfin led the largest host of the Noldor when they fled Aman for Middle-earth, even though he thought this unwise; he did not want to abandon his people to Fëanor. His followers participated in the Kinslaying at the Havens, but only because they arrived after the battle was underway not knowing that Fëanor was the aggressor. He led them across the ice of the Helcaraxë, an epic and arduous journey lasting many months, on which many of the people perished.

They arrived in Middle-earth at the first rising of the Moon, and sounded their trumpets. Soon after, at the first rising of the Sun, he came to the gates of Angband and smote upon them, but Melkor—now known as Morgoth—stayed hidden inside. Fingolfin and the Noldor then came to the northern shores of Lake Mithrim, from which the Fëanorian part of the host had withdrawn.

Fingolfin's son Fingon rescued Maedhros, son of Fëanor, who in gratitude waived his claim to kingship: thus, Fingolfin became High King of the Noldor. He then ruled from Hithlum, by the northern shores of Lake Mithrim.

After defeating the Orcs in the Dagor Aglareb, Fingolfin maintained the Siege of Angband for nearly 400 years. The Siege was ended by Morgoth's sudden assaults in the Dagor Bragollach, the Battle of Sudden Flame, and many peoples of Beleriand fled.