Many American authors expressed their concern that US competitiveness in science, technology, engineering, and mathematics (STEM) is losing ground. Using the Trends in International Mathematics and Science Study (TIMSS) 2007 data, this study investigated how academic self-concept and instrumental motivation influence science test performance among East Asian and American students. Jackknife regression modelling indicated that in East Asia science competency is not tied to enjoying science or estimated ability while in the US both variables are negatively correlated with performance. Additionally, the test performance of the East Asian students does not seem to be boosted by the perception of the role of science in career advancement, but this perception could significantly predict the test performance of their American counterparts. It is the conviction of the author that these findings related to student-level factors could lead to practical implications for educational policies and pedagogical strategies, such as placing emphasis on daily applications of science. (Contains 12 tables.)