The purpose of this study was to determine the influence of Project Based Learning toward the science process skills of students in class X SMAN 4 Sidoarjo. This study uses quasi experiment with pretest posttest non-equivalent control group design. The samples were considering similar cognitive abilities between two classes into a control group and an experimental group. Science process skills measured by a written test then analyzed by an assessment rubric that has been adapted to every aspect of science process skills. The results showed that there was the influence of Project Based Learning toward the science process skills of students.\Tujuan penelitian ini adalah untuk mengetahui pengaruh pembelajaran Project Based Learning terhadap keterampilan proses sains siswa kelas X SMA Negeri 4 Sidoarjo. Penelitian ini menggunakan metode Quasi Eksperimen dengan rancangan pretest postest non-equivalent control group design. Penentuan sampel mempertimbangkan kemampuan kognitif yang setara antara dua kelas yang menjadi kelompok kontrol dan kelompok eksperimen. Keterampilan proses sains diukur melalui tes tulis yang kemudian dianalisis dengan rubrik penilaian yang sudah disesuaikan untuk setiap aspek keterampilan proses sains. Hasil penelitian menunjukkan bahwa ada pengaruh pembelajaran Project Based Learning terhadap keterampilan proses sains siswa.