This study aims to improve students' learning activities in mathematics regarding the nature of waking space using the problem-posing model combination group investigation and 3D media. This research was carried out at SDN Benua Anyar 4 Banjarmasin, Indonesia. Subjects in this study were 12th-grade students. The type of research used is class action research. Data collection used observation and tests. Based on the results of data analysis, there was an increase in student activity in learning where 91.67% of students were in active and very active qualifications. Learning outcomes also increased where evaluation of the classical completeness cycle I reached 50%, 58% in the second cycle, 75% in the third cycle, and up to 91.67% in the IV cycle. It can be concluded that the application of problem posing models combined with group investigation and 3D media improves students’ achievement and learning activities in mathematics. Keywords—problem posing; group investigation; 3D Media; student activity; learning outcomes; mathematics