Tujuan penelitian ini untuk mengetahui pengaruh pendekatan Contextual teaching and Learning (CTL) terhadap hasil belajar biologi dan kemampuan berpikir kritis siswa. Penelitian ini dilaksanakan pada bulan November 2014 di Madrasah Aliyah Negeri Tarakan kelas XI IPA. Jenis penelitian ini adalah eksperimen semu dengan populasi siswa kelas XI IPA dan sampel sebanyak 2 kelas. Teknik pengambilan sampel menggunakan penarikan sampel berkelompok (cluster purposive sampling). Data analisis menggunakan uji MANOVA yang dilanjutkan dengan uji Independent sample ttest. Hasil analisis pengaruh pendekatan CTL terhadap hasil belajar biologi dan kemampuan berpikir kritis siswa diperoleh (F = 17,923; p < 0,05). Serta hasil uji Independent sample t-test terhadap pendekatan CTL dengan model konvensional ditinjau dari hasil biologi diperoleh thitung 5,723 pada taraf signifikansi 0,05 dan dk=74 diperoleh 1,6657 berarti t hitung > ttabel dan untuk kemampuan berpikir kritis siswa diperoleh thitung 2,236 pada taraf signifikansi 0,05 dan dk=74 diperoleh nilai ttabel 1,6657 berarti thitung > ttabel. Berdasarkan hasil analisis data dapat disimpulkan bahwa terdapat pengaruh pendekatan CTL terhadap hasil belajar biologi dan kemampuan berpikir kritis siswa.

The objective of this research was to determine the influence of Contextual Teaching and Learning approach to biology learning outcomes and critical thinking skills of students. This study was conducted in November 2014 in the eleventh grade of Madrasah Aliyah Tarakan. This research was a quasi - experimental with population was the students of the eleventh gradeand the sample was two classes.The sampling technique was using a sampling group (cluster purposive sampling). The data analysis was using MANOVA test followed by a test of Independent sample t-test. The results of analysis of the influence of CTL approach to biology learning outcomes and critical thinking skills of the students was (F = 17.923 ; p < 0.05) . As well as the results of Independent sample t-test for CTL approach with the conventional model in terms of the biological results was obtained thitung 5.723 at significance level of 0.05 and dk = 74 the result was 1.6657 which means thitung > ttable and for the critical thinking skills of students was obtained t hitung 2.236 at significance level 0.05 and dk = 74 the result was the score of t table 1.6657 which means thitung > ttable. Based on the results of data analysis, it can be concluded that there are influence of CTL Approach to Biology Learning Outcomes and Critical Thinking Skills of Students.