The Romance of the Forest by Ann Ward is about the secrets that eventually catch up with people, even if they try to escape. This theme is seen early on in the story, when Pierre de la Motte leaves Paris to escape imprisonment. The theme of dark secrets is also symbolically illustrated by the skeleton la Motte finds in the abbey. It is a literal "skeleton in the closet," vividly illustrating the figure of speech.

Everyone in this novel has a past they are trying to run away from. The claustrophobic nature of their respective and collective predicament, as well as their insulated household dynamics, intensifies the haunting effect of their past. As the title suggests, the other theme of the narrative is finding love. The novel, after all, ends in marriage and a joyous fairy tale ending, with Adeline marrying Theodore.

Thematically, The Romance of the Forest also plays with Gothic themes, such as supernatural forces and murder. Another theme of both Gothic novels and this novel is morality. The haunting past that la Motte is running away from is essentially the torment of wrestling with morality. The same can be said about Adeline's father and other dubious characters.