It was first published in the United Kingdom in October 2019 by Jo Fletcher Books, and is about a widow who buys a farmhouse in Yorkshire to start a new life, but is haunted by ghosts of the farm's former occupants.

Mistletoe generally received positive reviews from critics, and was nominated for the 2020 British Fantasy Society August Derleth Award for Best Horror Novel.

[3] Mistletoe features prominently in the novel, and Littlewood said she incorporated folklore surrounding the plant into the story, including the belief that it made it possible to talk to the dead.

"[3] In a review in The Guardian, Eric Brown called Mistletoe Littlewood's "best [novel] yet", adding that it is "a creepy, page-turning triumph enlivened with excellent folkloric details, beautiful descriptions of winter landscapes and sensitive characterisation.

[5] The reviewer said that while the novel's premise features often in literature, for example Hurley's Starve Acre, and du Maurier's The House on the Strand, Littlewood adds "plenty of new twists" to the theme with "a creeping sense of menace".

[6] Alyson Faye wrote in Horror Tree that Mistletoe is a "beautifully crafted seasonal novel", complete with "Victorian time-slip" and "gorgeous descriptions of the landscape, the farmhouse, and the scenes of Christmas.