TIMSS examines the effectiveness of curriculum and instruction in relation to student achievement, which makes the issue of assessment-curriculum alignment important to test developers and policy makers alike. While TIMSS assessments were developed to represent an agreed-upon framework and they were intended to have as much in common across countries as possible, it was inevitable that the match between test and curriculum would not be identical in all countries. This paper looks at issues of curriculum coverage and how non-coverage affects scale scores. Using non-covered items identified by the IEA Test-Curriculum Matching Analysis (Mullis et al., 2004), the items listed as non-covered for a particular country are removed from all countries. Next, the data are rescaled using item response theory (IRT) scaling methods and the resulting scale scores are correlated with the reported scale scores. This procedure is repeated using each country's list of non-covered items. The analysis shows that the scale scores for all items correlate very highly with curriculum-covered items for the country assessed. The results indicate that even if countries would have selected the items that are covered in their intended curricula, no statistically significant effects could be found in any country's international standings.