Penelitian ini bertujuan untuk mengetahui pengaruh model pembelajaran Problem Based Learning (PBL) terhadap keterampilan berpikir kritis siswa Geografi kelas X SMA Islam Diponegoro Wagir. Penelitian ini menggunakan pendekatan kuantitatif dengan jenis penelitian eksperimen semu (quasi experiment), serta menerapkan desain The Nonequivalent Control Group Design, yaitu dengan pemberian pre-test sebelum perlakuan dan post-test setelah perlakuan pada masing-masing kelompok. Teknik pengumpulan data meliputi observasi, dokumentasi, dan tes berbentuk esai. Uji coba instrumen dilakukan melalui uji validitas dan reliabilitas yang melibatkan siswa kelas XI IPS. Teknik analisis data menggunakan uji normalitas, uji homogenitas, dan uji hipotesis dengan independent sample t-test. Hasil analisis menunjukkan bahwa nilai signifikansi (2-tailed) adalah 0,000 < 0,05, sehingga Ha diterima dan Ho ditolak. Dengan demikian, model pembelajaran Problem Based Learning terbukti berpengaruh secara signifikan terhadap keterampilan berpikir kritis siswa. Penelitian ini memberikan kontribusi terhadap penguatan literatur tentang efektivitas model PBL, khususnya dalam konteks pembelajaran Geografi di tingkat SMA, serta menekankan pentingnya pendekatan pembelajaran yang mendorong keterlibatan aktif siswa dalam meningkatkan kemampuan berpikir tingkat tinggi. The Effect of Problem-Based Learning (PBL) on Geography Students' Critical Thinking Skills This study aims to investigate the effect of the Problem-Based Learning (PBL) model on the critical thinking skills of tenth-grade Geography students at SMA Islam Diponegoro Wagir. The research employed a quantitative approach with a quasi-experimental design, specifically using the Nonequivalent Control Group Design, in which both pre-tests and post-tests were administered to the experimental and control groups. Data collection techniques included observation, documentation, and essay-based tests. Instrument trials were conducted through validity and reliability tests involving eleventh-grade social science students. Data analysis techniques comprised normality tests, homogeneity tests, and hypothesis testing using the independent sample t-test. The results showed a significance value (2-tailed) of 0.000 < 0.05, indicating that the alternative hypothesis (Ha) was accepted while the null hypothesis (Ho) was rejected. Therefore, the Problem-Based Learning model has a significant effect on students' critical thinking skills. This study contributes to the existing body of literature by reinforcing the effectiveness of the PBL model, particularly in the context of high school Geography education, and highlights the importance of student-centered learning approaches in enhancing higher-order thinking skills.