While the United States (U.S.) and Canada share features in their secondary education systems (e.g. proportion of immigrants), these nations have differences (e.g. linguistic ). Given the primacy of Canada over the U.S. vis-à-vis science literacy [as measured by the Programme International for Student Assessment (PISA)], underlying differences in science dispositions and school climate variables could exist. The PISA 2015 science-focused dataset, including 5712 students in 172 schools in the U.S. and 20,058 students in 645 schools in Canada, was modelled via multilevel methods to assess associations among science dispositions (epistemology, enjoyment, interest, instrumental, self-efficacy activities) and science literacy. Associations of school climate variables of instructional leadership, disciplinary climate and teaching support (the latter two in the context of science classes) with the above measures were evaluated. Disciplinary climate was more often associated with science dispositions (as outcome measures) in the U.S., while teaching support was most often associated with these measures for Canada. Disciplinary climate was associated with science literacy (as an outcome measure) in the U.S.; in contrast, no school climate measures were associated with science literacy in Canada. These results support an emphasis on disciplinary climate in U.S. science classrooms, but an emphasis on teaching support in Canadian science classrooms.