Framed by Strayhorn's (2012) model of sense of belonging, this study examined the influence of academic and social collegiate experiences on the sense of belonging of undergraduate Latina students in science, technology, engineering, and mathematics (STEM) majors. "Sense of belonging" refers to a feeling of mattering or being connected and can be seen as a reflection of the supports that exist within a given context. This study used a qualitative, phenomenological approach to understand the lived experiences of 17 undergraduate Latina students majoring in STEM disciplines at a tier-one predominantly white public research university in the southwest. We found that Latina students often felt marginalized within their STEM environments, faced skepticism and self-doubt inflicted by their male peers, and were forced to navigate feelings of isolation during their college journeys. To build a sense of belonging, students actively resisted marginalization by reframing their experiences as trailblazing and engaging with identity-based STEM organizations. Implications for improving institutional practice and policy are discussed.