Research investigating retention in science, technology, engineering, and mathematics (STEM) attends to environmental and programmatic influences on student persistence. Examining these structures affords the creation of generalizable opportunities that promote sustained STEM engagement. In attending to the experiences of 5 Black women participating in a STEM undergraduate research program housed at a Historically Black University, this article explored structural influences on Black women's identity expression as it relates to their STEM engagement. Applying Phenomenological Variant Ecological Systems Theory to qualitative methodology, the influence of an antagonistic, oppressive STEM culture on Black women's identity expression and participation emerged, detailing the extent to which the institution and STEM programming combat and perpetuate said culture. Implications for creating and replicating STEM programming are provided.