Although there is increasing discussion of globalization as it relates to the importance of critical thinking skills of students in educational policies, the effectiveness of assessments for measuring critical thinking skills---in order to make valid comparisons---has not received much attention. The International Test Commission Guidelines on Adapting Tests recommends researchers to be aware of the cultural and linguistic context of the study as their first step. Researchers cannot simply assume that instruments work the same in all culture without empirical evidence. Validity evidence should be established prior to cross-cultural comparisons when an instrument is translated. To examine validity evidence for cross-cultural use of the Cornell Critical Thinking Test (CCTT) Level X Turkish form, this dissertation presents two studies: Study 1 investigates item level invariance, and study 2 examines the factor structure invariance of the CCTT across U.S. and Turkish samples. The results revealed that after critical content review the revised translation of the items on the CCTT function similarly for Turkish and US students. The results also suggested that items within their theoretically supported domains do measure the same skills equally across groups. However, practitioners and educators should be cautious in cross-cultural comparison of the scores given differences in the underlying factor structure.