Students are required to master critical thinking skill because they can train student in information management and logical decision making. The conduct of research is for the known influence of guided inquiry model in student' critical thinking skill. Research method used is quasi experiment with post test control group design which aims to obtain results from student' critical think skill and the known difference on critical thinking skill of student who are given the behavior model of teaching and conventional inquiry teaching. Student of class X IPS 1 and X IPS 2 at SMAN 1 Tile in the gasal semester of the 2020/2021 school year became a research sample of each class of 40 student. Data collection using LKS and post test question critical think skill. The results of this research showed the post test scores that there was a significant effect of using the guided inquiry learning model on the tenth grade students’ critical thinking skills, that can be seen there was a significant difference on the average value between the experimental class who taught by used the guided inquiry model and the class control who taught by using the conventional model, the students’ mean score of the experimental class was 90.85 and the score of control class is 77. Therefore, we can concluded that there’s significant effect of using the guided inquiry model on the tenth grade students’ critical thinking skills towards Geography subject at SMAN 1 Genteng. Siswa diharuskan menguasai keahlian berpikir kritis sebab bisa melatih siswa dalam pengelolaan informasi dan pengambilan keputusan logis. Dilakukannya penelitian ialah guna diketahuinya pengaruh model inkuiri terbimbing pada keahlian berpikir kritis siswa. Teknik penelitian yakni Quasi experiment dengan post test control group design guna mendapat hasil dari keahlian berpikir kritis siswa serta diketahuinya pembeda keahlian berpikir kritis siswa yang diberikan perilaku model belajar mengajar inkuiri terbimbing dan konvensional. Siswa kelas X IPS 1 dan X IPS 2 di SMAN 1 Genteng semester gasal tahun ajaran 2020/2021 menjadi sampel penelitian yakni setiap kelas 40 siswa. Pengumpulan data memakai LKS dan soal post test keahlian berpikir kritis. Hasil penelitian memperlihatkan model pembelajaran inkuiri mempunyai pengaruh dalam kemampuan siswa untuk berpikir kritis yakni nilai rata-rata yang dihasilkan berbeda antara kelas kontrol dengan model konvensional serta kelas eksperimen yang diberikan model inkuiri terbimbing yang mana nilai rata-rata 90,85 diperoleh dari kelas eksperimen sementara 77 ada pada kelas kontrol. Sehingga dapat disimpulkan kemampuan berpikir kritis siswa dalam ilmu pelajaran Geografi siswa kelas X IPS SMAN 1 Genteng dapat dipengaruhi dengan model inkuiri terbimbing.