The Tooth Fairy was generally well received by critics, and won the 1997 British Fantasy Society August Derleth Award for Best Novel.

[4] de Lint said Joyce lays bare "all the miserable angst and profound joys of childhood", making this "utterly riveting" reading for those who want to revisit "that emotionally charged time in their lives".

[5] It called the sprite "a fleur de mal [flower of evil] from childhood's secret garden", but added that the book's central allure is the three boys and the "gentle wit" Joyce uses to depict their "charmingly mischievous, naive and hormone-driven" lives.

[6] The reviewer felt that while the book's "central weakness" is its "traditional Bildungsroman narrative", it soars at the end when Sam and the fairy free themselves of each other.

[6] David Soyka wrote in a review at the SF Site that The Tooth Fairy is "a marvellous reminder" of the "turbulent physical and emotional transformations of adolescence".

[7] In another review at the SF Site, Margo MacDonald stated that while the book is "very well written" and "evoke[s] strong and disturbing images", she did not enjoy watching the boys grow up.