<p>The purpose of this study was to investigate the possible influence of disposition towards critical thinking, grade level and gender (as independent variables) on the quality level of secondary school students’ beliefs about science (as a dependent variable). A total of 141 Spanish secondary school students, 75 boys and 66 girls. in grades 8, 9 and 11 took part in this study. A questionnaire on beliefs about science and a questionnaire that maps disposition towards critical thinking were administered to participants. From the Pearson product-moment correlation matrix of the study variables and from the backward stepwise regression analysis it can be concluded that: 1) academic training received and gender seem to have a negligible impact on beliefs about science; and 2) disposition towards critical thinking (that is to say, potential use of critical thinking skills) makes an outstanding contribution to those beliefs</p>