There has been continued concern over the continued high dropout rate among Mexican origin youth. The purpose of this study is to understand how everyday experiences in school shape the content and meaning of Mexican origin students' social identities and how those social identities influence their academic trajectories over the transition to high school. This study is informed by a borderlands perspective and social identity theory and uses a qualitative design drawing from multiple sources of data, most of which come from The Student Life in High Schools Project (SLP), a longitudinal study of the transition to high school. The primary source of data for this project is the individual student interviews of thirty-two Mexican origin students attending a predominately Latino school from eighth grade through tenth grade of high school, contextualizing their experience within a specific community, historical, and political context. The Extended Case Method (ECM) grounded in a Chicana feminist epistemology was employed. The ECM itself combines qualitative research from various traditions and emphasizes a reflexive model of science allowing for an extension of existing theories. Findings focused on the construction of students' Mexican identities, school experiences that shape social identity, negotiating identity in the gang context, and developing academic identities in the context of teacher relationships. Student Mexican identities generally followed three patterns, that of an immigrant identity, a U.S. Mexican identity, or a U.S. minority identity. Academic identities identified in this study were: “underachiever”, “discouraged”, “tentative”, “solid”, and “troublemaker.” Students experienced a constant vulnerability in developing solid academic identities despite prior or current experiences of success. Some students drew on their cultural and family resources to persist in school despite serious obstacles, including the gang context. A framework for understanding the school experiences of Mexican origin youth and the process of identity development within a particular context is discussed. A model that addresses social identity and the context of students in West Park is presented. The study concludes with recommendations addressing the educational needs of Mexican origin youth in a way that recognizes the strengths they bring as they work to negotiate their social identity.