As one of the renowned learning and innovation skills of 21st century, critical thinking (hereafter CT) has been studied in various fields of education. Contrary to expectations, the emphasis on the mutual link between CT and language learning in tertiary education is newly flourishing. That being the case, the awareness of English as a Foreign Language (hereafter EFL) learners regarding this close connection and how it affects their perceived language learning potential should be inquired and increased. Drawing on such need, this paper reports on the investigation of an action research implementation and its effects on the perceptions of EFL learners over a ten week period of CT integrated practice. Qualitative and quantitative analysis of the data collected through two CT tasks, open-ended questionnaires, and semi-structured interviews based on learners' logs revealed an unequivocal influence on the perspectives of EFL learners towards CT and language learning. The implementation also helped the learners improve their thinking and language skills.