This study examined secondary science teachers’ conceptions of democratic citizenship and their beliefs about how citizenship relates to science education. These beliefs and conceptions were studied through a framework comprised of theories of belief, citizenship education, and civic engagement with science. Data were collected from 10 teachers representing a range of science courses through semi-structured interviews. Relevant documentation of their teaching was also collected and analyzed. The first finding of this study was that participants think of citizenship as an obvious and uncontroversial goal for their teaching. However, citizenship was found to be a nominal concern, while college and career readiness were the main justifications given for science education. Participants believed that citizenship and career aims were both met simultaneously by science education as currently practiced. The second finding indicated that participants worked from a simple model of “well-informed” citizenship in which science is to supply knowledge while citizens are to adopt and integrate this knowledge into their civic discourse. Teachers’ representations flattened the realities of how scientific knowledge is produced as well as used. Participants framed public-science dysfunction as a knowledge deficit problem that should be remedied by more effective means of top-down communication of facts. The third and final set of findings related to what participants felt were appropriate and effective ways for their teaching to address citizenship goals. Most participants sought to limit the presence of sociopolitical issues in their teaching. Such issues were sometimes mentioned as external points of reference meant to increase students’ motivation to learn traditional science content. Relatedly, participants also sought to maintain a professional border between science and other subjects. This mirrored the strict separation between science and politics they thought not only existed but served as a source of credibility for science. For participants who did feel it was appropriate to cross disciplinary borders to achieve civic aims, school structures and external mandates were cited as serious impediments. The study’s implication for teacher educators is that a deep belief in the power of traditional science teaching to overcome misinformation and citizens’ lack of trust in scientific experts must be addressed. Additionally, for those arguing for interdisciplinary teaching, attention must be paid not only to limitations imposed from outside the science classroom, but to the science teacher’s internal commitments to remain within their discipline.