International studies tend to use student, teacher, and/or school questionnaires to collect contextual data on student and teacher characteristics, background, and activities, and the school’s learning environment. Student measures of values, attitudes, and behavioral intentions are also often viewed as important learning outcomes, in particular within the context of studies of civic and citizenship education. The scaling of questionnaire items to obtain measures of students’, teachers’, and principals’ perceptions and attitudes should therefore ideally be subject to a thorough cross-country validation of the underlying constructs. However, whereas those conducting international studies spend considerable effort ensuring measurement equivalence for international test instruments, the issue of equivalency of questionnaire data does not always receive the same attention. Using a set of student questionnaire items as an example, this article describes different methodological approaches to assess cross-national construct validation. With reference to an example from the field trial analyses for the IEA International Civic and Citizenship Education Study (ICCS), the article also shows the extent to which classical item statistics, factor analysis, and item response modeling help to assess the construct validity of questionnaire data obtained from international studies.