The present study is part of a Ph.D. program that explores the possible effect of critical thinking-oriented dynamic assessment (CT-DA) on learners' learning potential in reading comprehension skills. 21 Iranian language learners who were homogenized in terms of their language proficiency, reading comprehension, and critical thinking abilities participated in this study. Learners were divided into three groups of CT-DA, dynamic assessment (DA), and Control group. While learners in CT-DA received mediation loaded with critical thinking techniques, learners in DA group received dynamic assessment mediation, and learners in the Control group did not receive any mediation. The analysis of the results revealed that DA and CT-DA significantly improve learners' reading potential scores. Moreover, significant differences between the Learning Potential Score (LPS) of DA and CT-DA groups were found, denoting the better performance of participants who received a critical thinking-oriented dynamic assessment. Finally, the qualitative analyses led to the detection of eleven mediational strategies which nurtured the development of the reading comprehension ability of L2 learners during CT-DA. The article concludes with suggestions for further research on dynamic assessment and critical thinking in second/foreign language development.