The effect of the implementation of student response systems (SRSs) in teaching on the critical thinking (CT) of young students was investigated. The study benefited from a quasi-experimental design and a pretest/posttest set-up. Subjects consisted of 156 K-8 students in Tehran during 2016-2017, selected through a multistage cluster sampling, and randomly assigned to either the experimental group (EG) or the control group (CG). The regular curriculum of the students contained a weekly session of a course titled "Thinking and Lifestyle." Ten sessions of the course were conducted using SRS (aka clickers) for EG, whereas CG kept receiving the same content in the conventional form. The teaching period was followed by the posttest. ANCOVA showed that, in contrast with CG, EG scored significantly higher on CT test after the intervention. The effect was shown to be only significant for the students at the lower side of the performance spectrum. Thus, in this inaugural study of clickers in schools in Iran, it was empirically demonstrated that clickers, as a relatively new piece of technology, can be successfully utilized during early adolescence in the pedagogical strategies in general and for the improvement of CT of students in particular.