the study reflected in this thesis aims at finding out relationships between critical thinking (ct), and the reading sections of tofel and ielts tests. the study tries to find any relationships between the ct ability of students and their performance on reading tests of tofel and academic ielts. however, no research has ever been conducted to investigate the relationship between ct and the reading sections of tofel and academic ielts tests. this study was conducted in three steps. the first step was to take the persian version of the watson-glaser critical thinking appraisal (wgcta) form a from 155 participants in three levels of intermediate, upper-intermediate, and advanced. the persian version was chosen to guarantee a complete understanding of ct by the participants rather than having them deal with language complexities of the ct test. the second step was to take the reading section of the tofel (2004). finally the third step was to administer the ielts (2003) academic reading. after the accumulation of the data, the scores on ct and tofel, ct and ielts, were computed through the pearson product-moment formula. the different performances of male and female participants, and the relationship between their age and ct were computed through the same formula. also, the point biserial correlation formula was used to discover any existing relationship between the participants’ gender and their ct. the findings demonstrated that there was a moderate correlation between ct and students’ performance on tofel (r= .38, p< 0.05) and ielts (r= .40, p< 0.05), and that there is a moderate correlation between males’ and females’ performance on these tests based on their ct scores: males’ ct and performance on tofel (r= .30, p<0.05), males’ ct and performance on ielts (r= .47, p<0.05), females’ ct and performance on tofel (r= .49, p<0.05), and females’ ct and performance on ielts (r= 0.38, p<0.05). the findings showed that men did better on the ielts tests and women on the tofel. this can be explained in two ways. the first explanation is that the difference is not that great to be significant, but the second explanation, on the other hand, would be that, psychologically speaking, men focus on the overall issue rather than details and that is how the ielts questions are built. conversely, women focus on details rather than the general idea, and that is how the tofel questions are made, and this is in line with what has been discussed in chapter three about the test forms in tofel and ielts tests. these results rejected the first two hypotheses and represented a relationship between the variables in question. the correlation between scores on ct and age revealed a very weak relationship between the two variables (r= .084, p<0.05). this relationship is so weak that can be neglected and although it rejects the third null hypothesis, further research is obviously needed to gain more conclusive results. finally, the results of the correlation between ct and gender revealed that there was no relationship between ct and gender (r= -.0472, and p> 0.05), suggesting that ct is not a gender based issue. and therefore, the fourth null hypothesis was retained.