Penelitian ini bertujuan untuk mengetahui kelayakan dari Lembar Kerja Peserta Didik (LKPD) Berorientasi Guided Discovery pada Materi Kimia Unsur Kelas XII SMA untuk Melatihkan Keterampilan Proses Sains (KPS). Kelayakan ditinjau dari aspek validitas, kepraktisan, dan keefektifan LKPD yang dikembangkan. Jenis penelitian ini merupakan penelitian 4-P dengan metode one group pretest and posttest design yang diuji cobakan terbatas pada 12 peserta didik kelas XII IPA di SMAN 1 Driyorejo Gresik. Instrumen penelitian yang digunakan yaitu lembar telaah, lembar validasi, angket respon peserta didik, lembar observasi aktivitas peserta didik, lembar keterlaksanaan pembelajaran dan lembar tes keterampilan proses sains. Hasil validitas ditinjau dari validitas isi dan konstruk. Pada validitas isi, LKPD 1-3 memperoleh persentase secara berturut-turut sebesar 83,91%, 83,91%, dan 85,00% dengan kategori sangat valid. Pada validitas konstruk ditinjau dari kriteria kebahasaan LKPD 1-3 memperoleh persentase secara berturut-turut sebesar 86,67%, 85%, dan 85% dengan kategori sangat valid. Pada kriteria penyajian, LKPD 1-3 memperoleh persentase secara berturut-turut sebesar 86,67%, 86,67%, dan 84,44% dengan kategori sangat valid. Pada kriteria kesesuaian tampilan, LKPD 1-3 memperoleh persentase sebesar 91,11% dengan kategori sangat valid.Kepraktisan diperoleh dari hasil respon peserta didik yang didukung oleh hasil aktivitas peserta didik dan keterlaksanaan pembelajaran. Hasil respon peserta didik memperoleh rata-rata persentase keseluruhan sebesar 99,405% dengan kategori sangat praktis. Hasil persentase aktivitas peserta didik memperoleh persentase keseluruhan sebesar 100% dengan kategori sangat praktis. Sedangkan hasil keterlaksanan pembelajaran, pada pertemuan I-III memperoleh persentase rata-rata secara berturut-turut sebesar 93,75%, 95,83%, dan 100% dengan kategori sangat praktis. Keefektifan LKPD ditinjau dari hasil tes komponen keterampilan proses sains yaitu pengamatan, merancang percobaan, analisis data dan membuat kesimpulan. Persentase hasil tes setiap komponen keterampilan proses sains secara berturut-turut sebesar 89,17%, 89,17%, 90,83%, 75,69%, dan 91,67%, sedangkanN-gain score setiap peserta didik memperoleh nilai ≥ 0,7 sehingga 100% peserta didik berada pada kategori tinggi. Dengan demikian, LKPD yang dikembangkan dapat dikategorikan layak.

The aim of this research is to determine the feasibility of Student Worksheets with Guided Discovery Oriented on Chemistry Elements Matter in XII Grade Senior High School to Train Science Process Skills. The feasibility are reviewed base on validity, practicability and effectiveness of the developed worksheet. This type of research is a 4-D with the method of one group pretest and post test design being tested limited to 12 students of XII Science Grade at SMAN 1 Driyorejo Gresik. The instrument used in this research were review sheets, validation sheets, student response questionnaires, observation sheets of student activities, learning implementation sheets and science process skills test sheets. The results of the validity are reviewed from the content and construct validity. On content validity, student worksheet 1-3 obtained a percentage of 83,91%, 83,91% and 85,00% respectively with very valid categories. On construct validity in terms of linguistic criteria, student worksheet 1-3 obtained a percentage of 86.67%, 85,00%, and 85,00% respectively with very valid categories. On the presentation criteria, student worksheet 1-3 obtained a percentage of 86,67%, 86,67%, and 84,44% respectively with very valid categories. On display suitability criteria, student worksheet 1-3 obtained a percentage of 91,11% with a very valid category. Practicability is obtained from the results of student responses that are supported by the results of student activities and the implementation of learning. The response results of students obtain an overall average percentage of 99,405% with a very practical category. The results of the percentage of student activities get an overall percentage of 100% with a very practical category. While the results of learning implementation, at the I-III meeting obtained an average percentage of 93,75%, 95,83% and 100% respectively in a very practical category. The effectiveness of student worksheet in terms of the results of tests of science process skills components, namely observation, designing experiments, analyzing data and making conclusions. The percentage of test results for each component of science process skills in a row is 89,17%, 89,17%, 90,83%, 75,69%, and 91,67%, while the N-gain score of each student gets a score of ≥ 0.7 so that 100% of students are in the high category. Thus, the developed student worksheet can be categorized as feasible.