By 1900 Catholic educators had opened over two hundred institutions of higher learning across the American landscape, most of which provided at least some measure of instruction in science. No fewer than a dozen built astronomical observatories, five trained physicians, and others made strong attempts to provide an education in engineering and other scientific fields. Despite these gains, the standard literature about history of science and medicine in nineteenth-century America offers very little regarding the distinct shape and contributions of this Catholic higher educational enterprise when it came to the teaching of science. Furthermore, how these institutions came to be well-established amidst so many non-Catholic colleges and universities stands out as an important question within the larger history of American higher education. This dissertation takes as its principal goal to explore the place of science in nineteenth-century American Catholic higher education. Its five core chapters investigate the teaching of science for male and female students at a mix of institutional settings and geographical locales where religion and science co-produced a broad range of outcomes. The details that I present will beneficially compel a revision of views that regard American Catholics and their schools as inattentive to or unconcerned with science. By taking a detailed and overdue look at the teaching of science by Catholics, I provide a valuable corrective to our understanding of American Catholic higher education, one that not only reveals Catholics attentive to science, but at times that they and their schools were quite good at teaching it during the nineteenth century. No longer should narratives about Catholics showing them as having little interest in the teaching of science be uncritically accepted.