<![CDATA[This research aims to know the influence of GI type of cooperative learning toward students’ critical thinking ability. This research design is prettest-posttest non equivalent group. Samples were IXb and IXc that was chosen through cluster random sampling. The quantitative data was obtained from the average value of test were analyzed using t-test and U test. The qualitative data was description of students’ activity. The results of this research showed that students’ critical thinking ability was increasing with average of gain was 0.30 and had low criteria. The average of percentage whole of students’ activity include teamwork, presentation, asking, and answer had precisely citeria (59.49%). However, the increase of students’ critical thinking ability increased significantly, so can be concluded that GI type of cooperative learning has significant influence in increasing this ability.Penelitian ini bertujuan untuk mengetahui pengaruh pembelajaran kooperatif tipe GI terhadap Kemampuan Berpikir Kritis (KBK) siswa. Desain penelitian adalah pretes-postes kelompok tak ekuivalen. Sampel penelitian adalah kelas IXb dan IXc yang dipilih melalui teknik cluster random sampling. Data kuantitatif berupa rata-rata nilai tes yang dianalisis menggunakan uji-t dan uji U. Data kualitatif berupa aktivitas belajar siswa yang dianalisis secara deskriptif. Hasilnpenelitian menunjukkan bahwa KBK siswa mengalami peningkatan dengan rata-rata gain 0.30 dan berkriteria rendah. Adapun Rata-rata persentase aktivitas siswa yang meliputi bekerja sama, menyajikan hasil akhir, bertanya, dan menanggapi secara keseluruhan berkriteria cukup (59.49%). Meski demikian, peningkatan KBK siswa terjadi secara signifikan, sehingga dapat disimpulkan bahwa pembelajaran kooperatif tipe GI berpengaruh signifikan dalam meningkatkan KBK siswa.Kata kunci : aktivitas belajar, GI, KBK]]>
