There are various misconceptions students have when studied quadrilateral which encourages efforts needed to overcome these misconceptions. This study aims at overcoming misconceptions by designing learning trajectories in the topic of Quadrilateral applying the Realistic Mathematics Education (RME). Design research carried out at one of junior schools in Garut was used in this research in which thirty-one grade VII students took the participation. The data were collected by providing activity sheets and student worksheets, interviews, and classroom observations. The findings suggest that the learning trajectory of quadrilateral consist of four activities, i.e., origami shape, finding the properties, sulid (stacking sticks), and origami puzzle. From these activities, students can understand the concept of a quadrilateral smoothly. In general, the learning trajectory of a series of learning games/activities can help students to understand, develop, and solve problems in various materials.