Alan Lee (born 20 August 1947) is an English book illustrator and film conceptual designer. He is best known for his artwork inspired by J. R. R. Tolkien's fantasy novels, and for his work on the concept design of Peter Jackson's film adaptations of Tolkien, The Lord of the Rings and The Hobbit film series.

Alan Lee was born in Middlesex, England, and studied at the Ealing School of Art.

Lee has illustrated dozens of fantasy books, including some non-fiction, and many more book covers. Among the numerous works by J. R. R. Tolkien that he has illustrated are the 1992 centenary edition of The Lord of the Rings, a 1999 edition of The Hobbit, the 2007 The Children of Húrin, the 2017 Beren and Lúthien, the 2018 The Fall of Gondolin, and the 2022 The Fall of Númenor. He has given numerous conferences, interviews and masterclasses, such as the one recorded at the Bibliothèque nationale de France in 2020, during the exhibition "Tolkien : voyage en Terre du Milieu".

Hans Velten writes that Lee was influenced by William Morris's graphic approach. He suggests that Lee was comfortable with Tolkien's acceptance of Morris, and accordingly made his Middle-earth illustrations more like Morris's style. In Velten's view, Lee's work, especially as concept artist on Peter Jackson's 2001–2003 The Lord of the Rings film trilogy, has influenced the audience's "collective imagination" of how places and people should look in Middle-earth.

Non-Tolkien books he has illustrated include Faeries (with Brian Froud), Lavondyss by Robert Holdstock, The Mabinogion (two versions), Castles by David Day, The Mirrorstone by Michael Palin, The Moon's Revenge by Joan Aiken, and Merlin Dreams by Peter Dickinson.

He has illustrated retellings of classics for young people. Two were Rosemary Sutcliff's versions of the Iliad and the Odyssey—namely, Black Ships Before Troy (Oxford, 1993) and The Wanderings of Odysseus (Frances Lincoln, 1995). Another was Adrian Mitchell's version of Ovid's Metamorphoses—namely, Shapeshifters (Frances Lincoln, 2009).

Lee made cover paintings for the 1983 Penguin edition of Mervyn Peake's Gormenghast trilogy. He also did the artwork for Alive!, a 2007 CD by the Dutch band Omnia, released during the Castlefest festival. Watercolour painting and pencil sketches are among the media that Lee commonly uses.

Lee and John Howe were the lead concept artists of Peter Jackson's Lord of the Rings films between 2000 and 2003. They were recruited by director Guillermo del Toro in 2008 for continuity of design in the subsequent The Hobbit films, before joining Jackson when he took over the Hobbit films project. Jackson has explained how he originally recruited the reclusive Lee. By courier to Lee's home in the south of England, he sent two of his previous films, Forgotten Silver and Heavenly Creatures, with a note from himself and Fran Walsh that piqued Lee's interest enough for him to become involved. Lee went on to illustrate and even to help construct many of the scenarios for the movies, including objects and weapons for the actors. For example his illustration of the tower of Orthanc was closely followed by the set designers of The Two Towers to create a "bigature" at 1:35 scale for close-up filming. He made two cameo appearances: in the opening sequence of The Fellowship as one of the nine kings of men who became the Nazgûl; and in The Two Towers as a Rohan soldier in the armoury (over the shoulder of Viggo Mortensen's Aragorn who is talking to Legolas in Elvish).