[3] Dave Langford reviewed The Hounds of the Morrigan for White Dwarf #93, calling it "A little kitchen-sinkish in its determined ransacking of Irish myth, but fun for young and old alike.

"[6] ‘’The Bulletin of the Center for Children's Books’’ at the University of Chicago said that "The prose is rather relentlessly ornamented, but the images are always concrete and, like the narrative, have vigorous strength.

[5] Joanne Hall, in Fantasy Faction, identified "a level of darkness in the book that would be surprising in a contemporary children’s novel ... one of the most unsettling sequences in the book occurs when the fleeing children are trapped inside the Morrigan’s giant thumbprint, a maze lined with nauseating blisters of sweat where nothing can live".

[2] Several writers have given The Hounds of the Morrigan as one of their favourite books or noted that it influenced them: O'Shea was working on a sequel at the time of her death.

In an obituary, David Fickling wrote; "The few brilliant chapters of the unfinished sequel are almost worth publishing alone: a Christmas card scene, candelit shop windows, carol singers and a robin... and into this cheerful scene rides the great Irish witch the Morrigan with her wild sisters, bringing mayhem and magic and mischief".