This study aims to determine the validity of the encyclopedia Mandailing ethnomedicine in the area Mount Sorik Marapi as a student learning resource in ethnobotany. Subjects according to material experts, learning experts, design experts, responses from lecturers, and also responses from students. This type of research is development research using the ADDIE model. This research only reached the development stage. The results showed that based on the assessment of material experts of 85.5%, learning experts of 91.75%, and design experts of 96.67%, the average assessment of biology lecturers was 91.33%, and the average assessment of students by 89.33%. It can be concluded that the encyclopedia of ethnomedicine is appropriate to be used as a learning resource that can be used by students to support learning in ethnobotany courses.