The Problem-based Learning model is increasingly popular in physics learning since it encourages students to think openly, actively, and reflectively. Thus, it affects students’ critical-thinking skills. Through the meta-analysis, this study discussed how Problem-based Learning improved students’ critical-thinking skills. In this study, the researchers employed the experimental design with a meta-analysis technique. The research had been conducted by collecting articles from Google Scholar, Scopus, and ERIC (Education Resources Information Center). A total of 122 articles had been obtained which then 15 articles were selected and analyzed through 5 stages, namely (1) Orientation, (2) Conceptualization, (3) Investigation, (4) Discussion, and (5) Conclusion. The results of this study indicated that the Problem-based Learning model was able to improve students’ critical-thinking processes from the elementary level to the tertiary level. However, research on the Problem-based Learning model toward students’ critical-thinking skills has not been done much in the field of physics-based on levels and dependent variables.