The aim of this study was to identify students' motivational beliefs in science and revealed the connections between the profiles and three cognitive dimensions of science achievement through the examination of the socio-economic status (SES) and gender covariates of the profile memberships. Latent profile analysis using science motivational beliefs was conducted, and resulted in a four-profile model. The emerging profiles were named "low motivation", "moderate motivation", "high motivation", and "high motivation with very high confident". The results showed that the boys were less likely to have "high motivation" and "high motivation with very high confidence" profiles than the girls. The students with high SES were more likely to belong to the high motivation groups. The differences between the mean scores of the students in different motivation profiles were statistically significant in all other pairwise comparisons, except for the comparisons between the low and moderate motivation profiles. Our findings suggest that students' motivation toward science should take an integrative approach to improve students' cognitive dimensions of science achievement by considering students' gender and SES.