The differences between the books - The Lord of the Rings, The Fellowship of the Ring (novel), and The Two Towers (novel) - and The Lord of the Rings (1978 film) are as follows.
- In the film's prologue it is suggested that Sauron learned the craft of Ring-making after the 19 lesser rings were made, whilst in the original story it is Sauron who teaches the Elven-smiths this ability.
- Another deviation suggests that the Last Alliance of men and elves were losing the war, which contradicts the original story.
- In the scene where Frodo finds out that his ring is the One Ring, Gandalf throws the Ring into the fireplace, as in the book, and Gandalf recites the Ring-inscription in the Black Speech, but only the first two lines, after which he says the entire inscription in English — but they never look for the inscription itself.
- As in Tolkien's novel, Saruman the White adopts the title "Saruman of Many Colors"; however, his robes are neither white nor multi-colored, but red.
- The film greatly condenses Frodo's journey from Bag End to Bree; for example, Crickhollow, Brandy Hall, and the Old Forest do not appear.
- The hobbits' first encounter with the Nazgûl: In the novel, Frodo hides separately from the other hobbits; in the film, together with them. The same is true for Jackson's version.
- The scene where the Nazgûl arrive in the hobbits' room and begin slashing at their beds only to find that they are not there, and pillows have been placed to form the figures of their bodies: not in the book, but it is in Bakshi's film version (as well as the Peter Jackson version).
- The High-elf Glorfindel whom the hobbits and Aragorn meet as they approach Rivendell is replaced by Legolas.
- Tom Bombadil does not appear in the film.
- Arwen does not appear, nor is she mentioned.
- Aragorn carries a broken sword (presumably Narsil) up to the Rivendell section of the story where he presents it to the council. However, the sword's reforging into Andúril is never shown (or mentioned) in the film, even though Aragorn carries an unbroken blade for the remainder of the film. Also, Aragorn identifies it as the "sword of Elendil of Gondor", but no connection between Elendil and Isildur (his son) is stated, only that the sword was used to cut the ring from Sauron's finger.
- Gimli appears to be about the same height as the rest of the non-hobbits in the fellowship.
- Éowyn makes only a brief appearance and has no spoken dialogue.
- The explosive-like "blasting-fire", here the "Fires of Isengard", appears as magical projectiles shot from Isengard itself.
- Éomer is portrayed as a renegade whom Gandalf finds; together, they save the day at Helm's Deep. In the book, he was present at the battle, and Gandalf arrives with Erkenbrand.