Girls are usually not the first people to come to mind at the mention of power. In fact, the traditional discursive construction of girls marks them as powerless. Nevertheless, this investigation has reached different conclusions about the power of girls in the representational realm and beyond. By centering my study on a figure whom I call the niña fatal, this dissertation claims that it is precisely the girlhood of this figure that makes her powerful because she is positioned at the intersection of age and gender. As her name suggests, she bears some resemblance to her archetypal ancestor, the femme fatale. Yet, the move into Spanish is deliberate since Spanish-language cultural production is central to her emergence, although the limited criticism that explores the niña fatal overlooks this fact. Moreover, in feminist criticism, girls tend to be eclipsed by the adult female subject. Thus, central to this dissertation is the act of bringing particular margins into focus. The picture that is rendered by this focal adjustment is an uncomfortable one because the niña fatal takes aim at the symbolic authority of the father through her girlhood sexuality. In her seduction of the stand-in father, monstrosity and vulnerability collide, generating a discursive trap: her femaleness dictates that she is to be blamed for his downfall, but as a child, she is to be held blameless. This trap is apparent in the three close readings I conduct of the niñas fatales of Rosa Chacel’s novel, Memorias de Leticia Valle (1945), Isabel Allende’s short story, “Niña perversa” (1989) and Lucrecia Martel’s film, La niña santa (2004). Yet, more than challenging our internalization of patriarchal discourses, these creators also respond to the socio-political and ideological crises of their time and space by employing the niña fatal to explore the constitution of deviating female subjectivities. Operating on the micro level within the family, the niña fatal initiates a decadence in patriarchy’s underlying power in/over society through her undermining of the symbolic order. Additionally, she showcases how unbecoming girls can “unbecome” the girls who remain powerless under the patriarchy’s rigid discursive practices. The final chapter of this study explores this further, moving from the representational realm to the real to examine the ways that girls and their image are being used to resist patriarchal violence in the fight against femi(ni)cide.