Self-concept is the most predictive motivational belief to science achievement. Intrinsic value has a stronger relationship than utility value with achievement. A few countries are exceptions for the international pattern. Motivational beliefs of East Asian ones have stronger relations with achievement. This study shed light on different motivational dynamics across countries. The study aims to investigate the relations between three adolescent motivational beliefs in science learning and science achievement within an international scope. Drawing on the expectancy-value theory, the expectancy and task value beliefs have different predictive magnitudes for explaining student achievement. However, the patterns may not be identical in every country from the cross-cultural perspective. The data of the eighth grade students from 26 countries participating in the Trends in International Mathematics and Science Study (TIMSS) 2011 were examined. The results showed that the degree of predictive power between the three motivational beliefs and science achievement from the strongest to the weakest is self-concept, intrinsic value and utility value in general. In the individual country analysis, while the majority of the countries fit the international pattern, a few are exceptions. Additionally, motivational beliefs of East Asian students, who rank the top but show the lowest motivational beliefs in a series of large-scale assessments, have relatively stronger associations with achievement among the 26 countries. The results of this study shed light on different motivational dynamics across countries.