This study aims to produce critical thinking-based essay items in biology subject matter of environmental change in class X SMA Se-Sungai Bahar, Muaro Jambi Regency. This study uses the RnD research method, with the ADDIE model used as a development model. (1) analysis, (2) design, (3) development, (4) implementation, and (5) evaluation. The types of data in this study are quantitative data and qualitative data. Data collection techniques used essay test sheets, needs analysis, expert validation and practitioner validation. While the data analysis technique was carried out using qualitative analysis to determine the validity of the instrument items based on critical thinking from experts and quantitative analysis which included validity and reliability tests at each stage. Based on the results that 1) the process of developing critical thinking-based essay item products has been carried out properly by following research procedures. 2) The teacher's perception of critical thinking-based essay items has a very good category and is feasible for testing. 3) students' perceptions of critical thinking-based essay questions have a good category and are feasible to try out. 4) the effectiveness of critical thinking-based essay items in biology subject matter of environmental change in obtaining the average pretest score of class X students of SMA Negeri 9 Muaro Muaro Jambi, namely 67.30. While the acquisition of students' posttest scores increased, namely 77.63. Meanwhile, the average pretest score for class X students of SMA Negeri 4 Muaro Muaro Jambi was 56.63. While the acquisition of students' posttest scores increased, namely 70.17. These results indicate that there is a difference in the average value of the critical thinking ability of class X SMA Negeri 9 and X SMA Negeri 4 Jambi before the pretest and after the posttest based on critical thinking items. Penelitian ini bertujuan untuk menghasilkan produk butir soal esay berbasis critical thinking pada mata pelajaran biologi materi perubahan lingkungan di kelas X SMA Negeri Se-Sungai Bahar Kabupaten Muaro Jambi. Penelitian ini menggunakan motede penelitaian RnD, dengan model ADDIE digunakan sebagai model pengembangan. (1) analisis, (2) desain, (3) pengembangan, (4) implementasi, dan (5) evaluasi. Jenis data dalam penelitian ini, yaitu data kuantitatif dan data kualitatif. Teknik pengumpulan data menggunakan lembar tes essay, analisis kebutuhan, validasi ahli dan validasi praktisi. Sedangkan teknik analisis data dilakukan dengan analisis kualitatif untuk mengetahui validitas instrumen butir soal berbasis critical thinking dari pakar ahli dan analisis kuantitatif yang mencakup uji validitas dan reliabilitas pada setiap tahapnya. Berdasarkan hasil bahawa 1) proses mengembangkan produk butir soal esay berbasis critical thinking telah dilaksanakan dengan baik dengan memngikuti prosedur penelitian. 2) Persepsi guru terhadap butir soal esay berbasis critical thinking memiliki kategori sangat baik dan layak untuk di uji cobakan. 3) persepsi siswa terhadap butir soal esay berbasis critical thinking memiliki kategori baik dan layak untuk di uji cobakan. 4) efektivitas butir soal esay berbasis critical thinking pada mata pelajaran biologi materi perubahan lingkungan di perolehan rata-rata nilai pretest siswa kelas X SMA Negeri 9 Muaro Muaro Jambi yaitu 67,30. Sedangkan perolehan nilai postest siswa mengalami peningkatan yaitu 77,63. Sedangkan perolehan rata-rata nilai pretest siswa kelas X SMA Negeri 4 Muaro Muaro Jambi yaitu 56,63. Sedangkan perolehan nilai postest siswa mengalami peningkatan yaitu 70,17. Hasil ini menunjukkan terdapat perbedaan nilai rata-rata kemampuan critical thinking siswa kelas X SMA Negeri 9 dan X SMA Negeri 4 Jambi sebelum di dilakukan preetest dan setelah dilakukan posttest butir soal berbasis critical thinking.