This study aims to examine the differences and impacts of the Problem-Based Learning (PBL) and the expository learning on critical thinking skills in the topics of Social Action, Social Interaction, and Identity for grade X students at SMAN Boyolangu in the 2023/2024 academic year. A quasi-experimental method was adopted, following a one-group pretest-posttest design with a nonequivalent control group. The data analysis included tests for normality, homogeneity, and a paired sample t-test. The pretest results showed an average score of 66.74, which increased to 75.00 in the posttest. The independent sample t-test yielded a significance value (2-tailed) of 0.000, which is less than 0.05, thus confirming the result as statistically significant. The paired sample t-test revealed that both the PBL and expository models led to differences in students' critical thinking development. PBL demonstrated a significant positive impact on students' critical thinking enhancement.