iarjelIARJELIARJEL2708-5120https://doi.org/10.47310/iajel.2021.v02i01.031Assessing the Use of You Tube Videos as a Digital Tool for Improving Critical Thinking in ESP Online Class: An Action ResearchShadiForutanianUniversity of Tehran, IranThis action research was interested to elaborate You Tube videos usage as a digital tool for improving critical thinking of ESP online class in Iran. There were 50 learners of accounting major which lasted for one semester. By a few approaches which included You Tube videos about lesson playing, learners’ and researcher’ reflection and roleplay. In present paper I have strongly emphasis on the reflection of learners about using You Tube videos. For examining the theme, thematic analysis was conducted that emerged from their reflections. Based on Ary (2021, as cited in Ary, Jacob, Irvine and Walker, 2021, p. 487) action research model, action research made of eight stage as reflect, plan, act, observe, reflect, plan, act and observe. The results showed that You Tube videos were interesting and attractive for learners and improved their critical thinking. Also, they provided more engagement and participation. Learners understand lessons better and could made relation between videos and contents of their lessons by visualizing. This study proved the potential of YouTube videos as digital tools for improving critical thinking.