Critical thinking skills are importantly possessed by students and it is better to habituate it since elementary school. An appropriate learning model will positively support this skill. This research was aimed at investigating the effect of Problem-Based Learning model on the critical thinking skills of elementary school students. This research applied the quasi-experiment method withnon-equivalent(pretest and posttest) control group design. The subjects of the research were grade V students of SD Negeri 1 Kediri. The instruments used in the control group and experiment group were tests. The tests were in the form of 5 essay questions. The pretest and posttest questions were tested on the control group and experiment group. The pretest questions were used to investigate students early skills in both groups. The learning model in the control group was non-PBL, while the learning model in the experiment group was Problem-Based Learning. The results of the posttests in the two groups were compared to investigate whether there was a difference between the control group and the experiment group. The data were analyzed using Independent Sample t-test. The results of the research showed that the hypothesis test was 3.877, in which t-test t table. It could be concluded that there was a significant effect of Problem-Based Learning on critical thinking skills.