<![CDATA[Thisresearch was aimedto describe the validity and practicality of LKS based problem solving development to improve creative thinking skills on Arrhenius acidbasetopic. The method was used research and development design (R D). Validity of thestudent worksheet was assessed based on aspects of legibility, construction, and conformity with KI-KD. Practicality of thestudent worksheet was assessed based on legibility, construction, and content conformity with KI-KD by teachers; aspects of legibility, attractiveness, and positive responses by students; as well as test the implementation of LKS in the learning process. The results of thisresearchindicated that problem solving based LKS to improve students' creative thinking skills on Arrhenius acid base was valid and practical to be used, itwasseen from the aspect of validity that has high criteria, teacher and student response to LKS of development result which has very high criteria, as well as positive responses from students after the learning process.Penelitian ini bertujuan untuk mendeskripsikan validitas dan kepraktisan pengembangan LKS berbasisproblem solvinguntuk meningkatkan keterampilan berpikir kreatif pada materi asam-basa Arrhenius. Metode yang digunakan adalah desain penelitian dan pengembangan (RD). Validitas dinilai berdasarkan aspek keterbacaan, konstruksi, dan kesesuaian isi dengan KI-KD. Kepraktisan dinilai berdasarkan aspek keterbacaan, konstruksi, dan kesesuaian isi dengan KI-KD oleh guru; aspek keterbacaan, kemenarikan, dan respon positif oleh siswa; serta uji keterlaksanaan LKS dalam proses pembelajaran. Hasil penelitian ini menunjukkan bahwa LKS berbasisproblem solvinguntuk meningkatkan keterampilan berpikir kreatif siswa pada asam basa Arrhenius sudah valid dan praktis digunakan, hal ini terlihat dari aspek validitas yang memiliki kriteria tinggi, respon guru dan siswa terhadap LKS hasil pengembangan yang memiliki kriteria sangat tinggi, serta respon positif dari siswa setelah melakukan proses pembelajaran.Kata kunci: asam basa Arrhenius, LKS,problem solving]]>
