The purpose of this article is to report findings from an ethnographic study that focused on the co-development of science literacy and academic identity formulation within a third-grade classroom. Our theoretical framework draws from sociocultural theory and studies of scientific literacy. Through analysis of classroom discourse, we identified opportunities afforded students to learn specific scientific knowledge and practices during a series of science investigations. The results of this study suggest that the collective practice of the scientific conversations and activities that took place within this classroom enabled students to engage in the construction of communal science knowledge through multiple textual forms. By examining the ways in which students contributed to the construction of scientific understanding, and then by examining their performances within and across events, we present evidence of the co-development of students' academic identities and scientific literacy. Students' communication and participation in science during the investigations enabled them to learn the structure of the discipline by identifying and engaging in scientific activities. The intersection of academic identities with the development of scientific literacy provides a basis for considering specific ways to achieve scientific literacy for all students.