ABSTRAK : Penelitian ini bertujuan untuk mengetahui pengaruh pendekatan saintifik terhadap kemampuan berpikir kritis siswa kelas IV SD.Penelitian ini dilakukan di SDN Jatikalang IIKrian dengan subjek penelitian adalah siswa kelas IV tahun pelajaran 2018/2019. Penelitian ini merupakan Penelitian Tindakan Kelas (PTK). Penelitian jenis kualitatif ini dilaksanakan dalam 2 siklus, peneliti menggunakan teknik observasi, dokumentasi,dan tes untuk memperoleh data. Teknik analisis data melalui tahap reduksi data, penyajian data dan penarikan kesimpulan dan verifikasi serta triangulasi data. Objek penelitian yaitu meningkatkan kemampuan berpikir kritis siswa yang dilihat melalui hasil tes setiap akhir siklus I dan II serta hasil observasi, dokumentasi dan wawancara. Hasil penelitian menunjukkan bahwa kemampuan berpikir kritis siswa dapat ditingkatkan melalui pendekatan saintifik pada subtema keberagaman makhluk hidup di lingkunganku. Hasil pertama menunjukkan bahwa kemampuan berpikir kritis siswa pada kelas IV. Hal ini ditunjukkan dengan hasil tes kemampuan berpikir kritis, persentase untuk kemampuan berpikir kritis siswa mengalami peningkatan dari rata-rata 71, 77% atau dalam kategori tinggi menjadi 87, 71%. Dengan demikian, kemampuan berpikir kritis siswa termasuk dalam kriteria sangat tinggi. Berarti ada pengaruh pendekatan saintifik terhadap kemampuanberpikir kritis. Dengan demikian dapat disimpulkan bahwa pendekatan saintifik berpengaruh terhadap kemampuanberpikir kritis. ABSTRACT : This study aim was to describe the effect of the scientific approach to critical thinking skills of fourth grade students. This research was conducted at Jatikalang II Krian Elementary School with the research subject being fourth grade students in the 2018/2019 academic year. This study is a Classroom Action Research (CAR). This type of qualitative research was carried out in 2 cycles, researchers used observation, documentation, and test techniques to obtain data. The technique of analyzing data is through the stages of data reduction, data presentation and conclusion drawing and verification and data triangulation. The object of research is to improve students' critical thinking skills which are seen through the test results at the end of the first and second cycles and the results of observations, documentation and interviews. The results showed that students' critical thinking skills could be improved through a scientific approach to the sub-themes of diversity of living things in my environment. The first results show that students' critical thinking skills in class IV. This is indicated by the results of the critical thinking ability test, the percentage for students' critical thinking skills has increased from an average of 71, 77% or in the high category to 87, 71%. Thus, students' critical thinking skills are included in the criteria of very high. Means there is an influence of the scientific approach to critical thinking skills. Thrus it can be concluded that the scientific approach affects the ability to think critically.