This study investigated the relationship between critical thinking and the writing ability of Iranian EFL learners, on the one hand, and the interrelationship among the sub skills of the two constructs, on the other. Furthermore, it aimed at finding which skills of critical thinking predicated the teachers’ writhing ability. To this end, 104 students majoring in English took the California Critical Thinking Skills Test (CCTST) and the writing section of a retired IELTS test, which urged them to develop an argumentative essay. Their essays were scored by 2 experts in the filed against the four subskills dictated by the IELTS test rubrics and descriptors. Result of the correlation and multiple correlation analyses indicated that although a significant correlation was observed between critical thinking and writing ability, it was not strong and meaningful. In addition, among the subskills of writing ability, only “organization” was found to be correlated with certain subskills of critical thinking. Multiple regression analysis revealed that among the five components of critical thinking, “analysis” and “evaluation” turned out to be significantly stronger predictors of writing ability.
