Penelitian ini bertujuan menghasilkan perangkat pembelajaran materi geometri ruang SMP dengan memanfaatkan alat peraga manipulatif dan lingkungan yang valid, praktis, dan efektif. Penelitian pengembangan ini menggunakan model pengembangan Four-D yang dimodifikasi menjadi tiga tahap: pendefinisian, perancangan, dan pengembangan. Uji pengembangan dilakukan di SMP N 1 Dukuhseti, Pati, Jawa Tengah. Instrumen pengumpulan data meliputi lembar validasi perangkat, lembar observasi keterlaksanaan pembelajaran, lembar penilaian kepraktisan perangkat, dan instrumen penilaian hasil belajar. Analisis data dilakukan secara deskriptif kuantitatif. Hasil penelitian ini berupa perangkat pembelajaran yaitu: RPP, LKS, Lembar Observasi Sikap (LOS) dan Tes Hasil Belajar (THB) dengan tingkat kevalidan 100%.  Tingkat kepraktisan LKS, RPP, dan LOS 100% sedangkan tingkat kepraktisan THB 84,36%. Tingkat keterlaksanaan pembelajaran 97%. Tingkat keefektifan RPP dan LKS 81%. Dapat disimpulkan bahwa produk hasil pengembangan yang berupa RPP dan LKS memenuhi kriteria valid, praktis, dan efektif, sedangkan instrumen penilaian yang berupa LOS dan THB  memenuhi kriteria valid dan praktis. Kata kunci: alat peraga manipulatif, geometri ruang, lingkungan, pengembangan perangkat.   Developing Instructional Materials in Space Geometry for Junior High School Using Manipulative Visual Aids and Environment   Abstract The aims of this research was to result instructional materials in space geometry for junior high school using manipulative visual aids and environment that valid, practical, and effective. This development research using the Four-D development model with modification in three steps: define, design, and develop. The development testing was carried out in SMP N 1 Dukuhseti, Pati, Central Java. The research instruments were a validation sheet, teaching implementation observation sheet, practicality assessment sheet, and competency assessment instrument. The data analysis was conducted quantitative descriptively. This research produced instructional materials including lesson plans, student’s worksheets, observation sheet of attitude, and assessment instrument with the level of validity of the product reached 100%. The degree of practicality lesson plans, worksheets, and observation sheet of attitude were 100%, while the rate of assessment instrument of learning achievement practicality was 84.36%. The level of learning was 97%. The degree of effectiveness of the lesson plans and worksheets products reached 81%. Therefore, it can be concluded that the instructional materials in the form of lesson plans and worksheets were valid, practical, and effective, while the form of assessment instruments observation sheet of attitude, and assessment instrument of learning achievement were valid and practical. Keywords: manipulative visual aid, space geometry, environment, instructional development