This paper compares and contrasts school science achievement between two top scoring nations, Japan and Singapore, on the Third International Mathematics and Science Study (TIMSS) assessments. The first part of the study is devoted to examining cross-national comparisons on selected background questions administered in the TIMSS survey, while the second part examines selected educational attributes and practices that might help explain their consistently high achievement in science. Attention to TIMSS data has chiefly focused on the achievement gap between US and other nations. This report moves beyond US deficit comparisons to examine results and programs of high achieving nations to better inform efforts to close the gaps.