Attitudes toward science are an important aspect of students' persistence in school science and interest in pursuing future science careers, but students' attitudes typically decline over the course of formal schooling. This study examines relationships of students' attitudes toward science with their perceptions of science as inclusive or non-religious, and their epistemological beliefs about epistemic authority and certainty. Data were collected using an online survey system among undergraduates at a large, public US university (n = 582). Data were prepared using a Rasch rating scale model and then analyzed using multiple-regression analysis. Gender and number of science and mathematics courses were included as control variables, followed by perceptions of science, then epistemological beliefs. Findings show that respondents have more positive attitudes when they perceive science to be inclusive of women and minorities, and when they perceive science to be incompatible with religion. Respondents also have more positive attitudes toward science when they believe scientific knowledge is uncertain, and when they believe knowledge derives from authority. Interpretations of these findings and implications for future research are discussed.