ABSTRAK Penelitian ini bertujuan untuk mendeskripsikan pengaruh,, besar pengaruh dan respon peserta didik terhadap penerpan model prolem based learning berbantu LKPD terhadap kemampuan berpikir kritis peserta didik di SMA Negeri 4 Kota Bengkulu, jumlah sampel pada penelitian ini sebanyak 66 siswa yang diambil melalui teknik random sampling. Adapun jenis penelitian ini quasi experiment dengan menggunakan rancangan pretes t-posttest control group design. Adapun instrumen yang digunakan dalam penelitian ini adalah tes kemampuan berpikir kritis dan angket respon peserta didik. Hasil dari penelitian ini menunjukkan bahwa penerapan model problem based leaning berbantuan LKPD berdasarkan uji sampel t-tes memperoleh nilai signifikansi 0,000 ≤ 0,05 yang menunjukkan bahwa terdapat perbedaan kemampuan berpikir kritis antara kelas kontrol dan kelas eksperimen, berdasarkan perhitungan effect size didapatkan hasil 1,13 yang dikategorikan tinggi. Serta respon peserta didik terhadap penerapan model problem based learning untuk meningkatkan kemampuan berpikir kritis peserta didik didapatkan persentase sebesar 76% dalam kategori sangat baik. Berdasarkan hasil beberapa uji diatas dapat disimpulkan bahwa penerapan model problem based learning berbantu LKPD dapat meningkatkan kemampuan berpikir kritis peserta didik. Kata kunci : model problem based learning, LKPD, kemampuan berpikir kritis ABSTRACT This research aims to describe the influence, influence and response of students to the application of the problem based learning model assisted by LKPD on students' critical thinking abilities at SMA Negeri 4 Bengkulu City. The population of this study were students of class XI MIPA SMA Negeri 4 Bengkulu City. The total sample in this study was 66 students taken using random sampling techniques. This type of research is a quasi experiment using a pretest t-posttest control group design. The instruments used in this research were critical thinking ability tests and student response questionnaires. The results of this research show that the application of the problem based leaning model assisted by LKPD based on the sample t-test obtained a significance value of 0.000 ≤ 0.05 which shows that there is a difference in critical thinking abilities between the control class and the experimental class, based on the effect size calculation the results were 1, 13 are categorized as high. As well as students' responses to the application of the problem based learning model to improve students' critical thinking skills, a percentage of 76% was obtained in the very good category. Based on the results of several tests above, it can be concluded that the application of the problem based learning model assisted by LKPD can improve students' critical thinking abilities. Keywords: Problem Based Learning Model, LKPD, Critical Thinking Skills.