This study aims to explain the Metaverse application development process for teaching geometry in a virtual reality environment. The application was developed based on the instructional design model including analysis, design, development, implementation and evaluation phases. The target group was secondary school students. During the analysis phase, students' virtual reality experiences and their needs for using the Metaverse application academically were identified. Additionally, learning outcomes from the Secondary School Mathematics Course Curriculum were selected to determine the application content, and convenient educational software programs for a Metaverse environment were examined. During the design phase, Metaverse software that was suitable for the study's purpose was selected. Also, three-dimensional models of the objects and the environment for the application activities were designed through three-dimensional drawing programs. During the development phase, the activities' visualization and manipulation trials were conducted by transferring the three-dimensional designs into the Metaverse application. After necessary corrections, activities took their final form. During the implementation phase, 15 students in grade 10th used the Metaverse application. During the evaluation phase, participants stated their opinions about the application. Accordingly, suggestions for improving the Metaverse application in the field of teaching geometry and its widespread implementation were proposed.