Tujuan penelitian ini untuk mengetahui perbedaan model Problem Based Learning dengan model Guided Inquiry ditinjau dari pemahaman konsep dan kemampuan berpikir kritis siswa kelas VII SMP Negeri 10 Tarakan. Penelitian ini dilakukan mulai bulan Mei- Juni 2015 di SMP Negeri 10 Tarakan. Penelitian ini menggunakan metode eksperimen semu (quasi eksperiment) dengan populasi seluruh siswa kelas VII SMP Negeri 10 Tarakan Tahun Ajaran 2014/2015, dan sampel yaitu kelas VII-3 sebagai kelas eksperimen I, kelas VII-4 sebagai kelas eksperimen II dan kelas VII-2 sebagai kelas kontrol. Teknik pengambilan sampel menggunakan Purposive Sampling dan teknik pengumpulan data menggunakan dokumentasi, observasi dan tes uraian. Data dianalisis menggunakan software SPSS 22.0 for Windows. Berdasarkan hasil analisis data disimpulkan bahwa terdapat perbedaan pemahaman konsep antara siswa yang diajar dengan menggunakan model Problem Based Learning, model Guided Inquiry dan model pembelajaran langsung pada kelas VII SMP Negeri 10 Tarakan, karena hasil uji One Way ANOVA diperoleh nilai probabilitas adalah 0.000 < 0.05. Dan selain itu juga dapat disimpulkan bahwa terdapat perbedaan kemampuan berpikir kritis antara siswa yang diajar dengan menggunakan model Problem Based Learning, model Guided Inquiry dan model pembelajaran langsung,pada Kelas VII SMP Negeri 10 Tarakan, karena hasil uji One Way ANOVA diperoleh nilai probabilitas adalah 0.000 < 0.05.

Kata kunci: model Problem Based Learning, Guided Inquiry, Pemahaman Konsep dan Kemampuan Berpikir Kritis.

The research was aimed to determine the differences of Problem Based Learning model and Guided Inquiry model in student’s concept understanding and critical thinking ability of grade VII SMP Negeri 10 Tarakan. The research was done from Mei to Juni 2015 at SMP Negeri 10 Tarakan. This is quasi-experimental study (quasi experiment) and the population for this study was the students in all grade VII of SMP Negeri 10 Tarakan ineven semester 2014/2015, and the sample was from grade VII-3 as the experiment class I, grade VII-4 as the experiment class II and VII-2 as the control class the sampling technique using purposive sampling and data collection techniquies using documentation, test, and observation. The data that had been obtained was analyzed by using SPSS 22.0 for windows software. Based on the results of data analysis, it can be concluded that there are differences between student’s concept understanding that had been taught using Problem Based Learning model with Guided Inquiry model, and Direct Intruction model on grade VII Negeri 10 Tarakan because the result of test One Way ANOVA had been obtained probability value is 0.000 < 0.05. And it can also be concluded that there are differences critical thinking ability between student’s taught using Problem Based Learning model with Guided Inquiry model, and Direct Intruction model on grade VII Negeri 10 Tarakan because the result of test One Way ANOVA had been obtained probability value is 0.000 < 0.05. Key Words: Problem Based Learning model, Guided Inquiry, Concept Understanding and Critical Thinking