Certain scientific conclusions are controversial, in that they are rejected by a substantial proportion of nonscientists despite an overwhelming scientific consensus. Science educators are motivated to help students understand the evidence behind the scientific consensus on these matters and to move students' views into alignment with those held by the vast majority of scientists, but their efforts are not always successful. In this article we use large-scale survey data to explore the nature, extent, and determinants of student resistance to scientific conclusions about evolution, anthropogenic climate change, and the importance of vaccination. We conclude that much student resistance has its source in identity-protective cognition, whereby science denial helps safeguard an individual's identity within a specific social group. Our findings indicate that for these students, supplying information is not enough to foster acceptance of scientific conclusions, and they suggest the need for interventions that address the connection between student identity and the acceptance of certain scientific conclusions.