Half-orcs are a race of half-Orc, half-Men from J. R. R. Tolkien's trilogy The Lord of the Rings. Half-orcs do not appear in until the second book (or technically speaking, the first book of the second part), The Two Towers, in the course of which the treacherous wizard Saruman sends them on an all-out offensive against the Men of Rohan.

Half-orcs are not a natural product of Middle-Earth evolution, just as the Orcs and Trolls are not. They were created by the sorcery of Saruman the White, the strongest of the Istari and leader of the White Council. Using unknown crafts he mixed the blood of his allies, the Men of Dunlend, with that of Orcs and Uruk-Hai. The result was the race of Half-orcs; tall, black-skinned, black-blooded and lynx-eyed. They were among the strongest servants of Saruman during the War of the Ring, due to their combination of both exceptional strength and deadly cunning. Furthermore, they did not fear sunlight as the Orcs did, so could travel in theory twice as fast on average. This made them far more effective footsoldiers than the average Orc, and often they served as captains or commanders in battle. Although not as physically strong as the incredible Uruk-Hai, they were possessed of greater intelligence and understanding of battlefield strategy.

Due to their relative infancy as a race, the vast majority of the Half-orcs perished at the Battle of Hornburg, when they failed to take the fastness of Helm's Deep from the Men of Rohan. Those who survived the assault followed the Wizard in his final petty offensive against the Shire; where they were, ironically, defeated by the Hobbits and were wiped out for good.