Penelitian ini bertujuan untuk menghasilkan produk berupa perangkat pembelajaran bangun ruang SMP dengan pendekatan problem-based learning yang valid, praktis, dan efektif dilihat dari pencapaian kompetensi dasar, kemampuan berpikir kritis, dan sikap terhadap matematika. Jenis penelitian ini merupakan penelitian pengembangan model 4D yang meliputi tahap pendefinisian, perancangan, pengembangan, dan tahap disseminasi. Hasil penelitian berupa perangkat pembelajaran bangun ruang yang terdiri atas silabus, RPP, LKS, dan instrumen evaluasi berupa tes pencapaian kompetensi dasar dan kemampuan berpikir kritis yang valid, praktis, dan efektif. Kevalidan perangkat mencapai kategori sangat baik ditinjau dari penilaian para ahli. Kepraktisan perangkat mencapai kategori sangat baik ditinjau dari penilaian guru, penilaian peserta didik, dan observasi keterlaksanaan pembelajaran. Aspek keefektifan dipenuhi dari tercapainya minimal 75% peserta didik lulus KKM ditinjau dari pencapaian kompetensi dasar dan berpikir kritis, serta lebih dari 80% peserta didik mempunyai sikap terhadap matematika dalam kategori tinggi. Dari kegiatan ekperimen diperoleh bahwa perangkat yang dikembangkan lebih efektif daripada perangkat pembelajaran konvensional ditinjau dari pencapaian kompetensi dasar, berpikir kritis, dan sikap terhadap matematika. Kata Kunci: pengembangan, perangkat pembelajaran, pendekatan problem-based learning, bangun ruang SMP   DEVELOPNING SPACE LEARNING KITS IN JUNIOR HIGH SCHOOL WITH PROBLEM-BASED LEARNING APPROACH Abstract This study was aimed to produce space learning kits with problem-based learning approach in Junior High School which was valid, practical, and effective based on achievement of basic competence, critical thinking skill, and attitude towards mathematics. This study was and development study using the 4D development model that included defining, designing, developing, and  disseminating phase. This study produced valid, practical, and effective space learning kits that consisted of syllabus, lesson plans, students’ worksheets, and assessment tests that included test of basic competence achievement and critical thinking test. Kits validity gets very good category from expert assessment. Kits practically gets very good category from teachers assessment, students assessment, and observation of learning implementation. The aspect of effectiveness was seen from achievement minimal 75% of the student pass the minimum score for achievement of basic competence and critical thinking skill, and more than 80% of student have attitude toward mathematics in high category. The result of experiment activity shows that the developed learning kits more effective than conventional learning kits based on achievement of basic competence, critical thinking, and attitude toward mathematics. Keywords: development, learning kits, problem-based learning approach, space