Julia is the novel’s female protagonist and the character around whom most of the plot revolves. She has auburn hair and dark eyes, “full of fire, but tempered with modest sweetness” (6). Radcliffe here emphasizes that Julia is young and passionate but that her passion is tempered with important traits that will bring her back to reason. The younger sister of Emilia and elder sister of Ferdinand, she displays a greater sense of feeling and ability to be stirred by passions than her siblings. Julia is raised and educated by Madame de Menon, and she demonstrates a quick intelligence and a talent for music and harmony. It is her uncommon musical talent that puts the seal on Hippolitus’s love for her.

Julia represents the dual sides of womanhood that were valued in the 18th century, being intelligent and accomplished but also resolutely honest and pure of heart. Her honesty is most often repaid with patriarchal tyranny that forces her to take bold action: Though she tells the duke and the marquis of her objections to the arranged marriage, they insist that she go through with it, and she escapes; when she confesses this tale to the Abate, he insists that she become a nun, and she escapes once more.