Mathematical communication is a fundamental skill needed by students. An application of ICT-based learning media, such as GeoGebra, using correct approach may increase mathematic communication. Therefore, this research aimed to analyze the effect of GeoGebra-assisted EPIC-R learning in improving students' mathematical communication skills. The study was sequential and explanatory research consisting of a sample size of 35 students from the Mathematical Education program at UIN Walisongo. The treatment class was treated using GeoGebra-assisted EPIC-R learning in geometry courses. Mathematical knowledge was observed from students’ communication skills while explaining answers to an assignment and formative assessment. The GeoGebra and formative assessment were used as the X1 and X2 variables. Meanwhile, students' answers from the formative assessment worksheet, which consists of their communication level, are used as the Y variable. The results showed that the X1 and X2 variables significantly affected Y by 24%, which means that applying GeoGebra-assisted with EPIC-R learning increases students' understanding of geometry and mathematical communication skills. However, this research is limited by providing significant reasons why students provide incomplete and insufficient answers. Therefore, further studies need to be carried out to understand students' mathematical communication by observing their main problems in explaining solutions.