This dissertation outlines findings from a critical ethnographic research study that attempted to document young Latinas engaging in critical mathematics education, with implications for shifting dominant ideas about the form and goals of education. As Latina youth are marginalized from classrooms and in society where their language, culture, practices, and community are seen as "problems," and particularly in mathematics classrooms where a dominant culture is said to further exclude girls (Walkerdine, 1998), there is an exigency to understand how in fact Latina students could experience education as transformative. Critical race and feminist/feminista theories further argue for centralizing the experiences of women or girls of color as essential to understanding where change can happen in society because of the role that racism and sexism play in structuring educational experiences. Therefore, this study foregrounds the experiences of young Latinas as they engage in critical mathematics. A critical educational paradigm has been put forth in which the purpose is to develop critical literacy in students where they investigate, make apparent and challenge oppressive societal structures. This critical ethnographic research study seeks to gain a more nuanced understanding of how young Latinas experience and shape a social justice mathematics learning environment through the facilitation and research of an after-school, all girls mathematics club. More specifically, data in the form of field notes, videotaped sessions, classroom observations, collection of student work and interviews offers a rich source for analysis of their practices in the learning environment, their perceptions of mathematics, themselves as learners of mathematics and as people who can make changes in their lives, communities and in the world. The construct of critical mathematical agency is employed in attempting to understand how the participants' actions expressed a sense of being able to use mathematics to critique and change their worlds. Analysis revealed they engaged in resistance, research and (re)authoring, as ways of expressing critical mathematical agency. In addition, their insight into critical mathematics education speaks to the importance of incorporating critical funds of knowledge, fostering collectivity, and centering the experiences in authentic, community based contexts. This understanding will inform arguments for seeking social justice through mathematics education and educational research, particularly for Latina youth.