A view of science as a culturally-mediated way of thinking and knowing suggests that learning can be defined as engagement with scientific practices. How students engage in school science is influenced by whether and how students view themselves and whether or not they are the kind of person who engages in science. It is therefore crucial to understand students' identities and how they do or do not overlap with school science identities. In this paper, we describe four middle school African American girls' engagement with science. They were selected in the 7th grade because they expressed a fondness for science in school or because they had science-related hobbies outside of school. The data were collected from the following sources: interviews of students, their parents and their teachers; observations in science classes; journal writing; and focus groups. These girls' stories provide us with a better understanding of the variety of ways girls choose to engage in science and how this engagement is shaped by their views of what kind of girl they are. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 441–458, 2000.