It is a psychological novel with a supernatural twist, featuring a thirteen-year-old boy's reaction to his mother's courtship and remarriage six years after his father's death.

Beside the inner themes, it "tells of a boy and his family brought to the brink of destruction by sinister external forces"[2] and it may be called a ghost story.

By conferring the 1981 Carnegie Medal, the Library Association named The Scarecrows the year's best book for children or young adults written by a British subject.

Simon ... loathes his stepfather and resents his mother's marital happiness; and it is obviously his own fury and malice that brings to life the Scarecrows, grown from clothes left in the nearby ruined water-mill by the participants in a long-past murderous triangle of passion.

"[5] The effectiveness of the horror aspect of the story is emphasised in Reading for Enjoyment, in which it is described as a "book to make the hairs rise on the back of your neck".