When Elidor was first published, Library Journal suggested it for grades five through seven, but it is not always easy to say what age group Garner's novels are written for. Some critics suggest that he writes for adults, but Garner himself has stated that his early books were written with young people of ages ten to eighteen in mind. Gamer has stated that he attempts to create works with several layers of meaning so that they can be read and enjoyed by young people of various ages.

When Elidor was published, some thought it might be "too terrifying" for young people. Although the novel has some frightening scenes, it does not seem terrifying by today's standards.

Readers may need to discuss the implications of the downbeat ending, which some find depressing.