Penelitian ini bertujuan untuk mengetahui perbedaan kemampuan berpikir kritis siswa sebelum dan setelah penerapan model project based learning dengan pendekatan Science, Technology, Engineering, Arts, and Mathematics (STEAM ). Penelitian ini dilaksanakan di MTs. Al Asyhar Gresik. Pengambilan sampel menggunakan teknik purposive sampling, yakni siswa kelas VIII A. Metode penelitian yang digunakan dalam penelitian ini menggunakan pre-experimental design dengan One group pretest-posttest design. Penelitian ini menggunakan penelitian kuantitatiflitatif dengan pengumpulan data berupa observasi, tes, angket, dan dokumentasi. Teknik analisis data menggunakan uji non parametrik (Uji Wilcoxon). Kemampuan berpikir kritis siswa sebelum dan setelah penerapan project based learning dengan pendekatan STEAM cukup signifikan. Hasil persentase rata-rata kemampuan berpikir kritis siswa pada pretest sebesar 35,45% dengan kategori rendah. Hasil persentase rata-rata kemampuan berpikir kritis siswa pada posttest sebesar 62,73% dengan kategori tinggi. Kata Kunci: Berpikir Kritis, Project Based Learning, STEAM This study aims to determine the differences in students’ critical thinking ability before and after the implementation of project-based learning with the STEAM approach. This study was conducted in MTs Al Asyhar Gresik. Purposive sampling was used on class VIII-A students as a sampling technique. The research method used in this study was a pre-experimental design with one group pretest-posttest design. This research employed quantitative research with data collection of observation, tests, questionnaires, and documentation. The data analysis technique used a non-parametric test (Wilcoxon test). The student’s critical thinking ability before and after the implementation of project-based learning with the STEAM approach is quite significant. The result average percentage of students’ critical thinking ability on the pretest was 35,45% in the low category. On the other hand, the average percentage of students’ critical thinking ability in the post-test was 62,73% in the high category. Keywords: Critical Thinking, Project Based Learning, STEAM.