Teachers support metacognition by following different teaching methods in face to face learning environments. However, literature shows that web based learning environments lack of the use of tools which support and guide the students' metacognitive activities. The primary purpose of this study is to give insight about development of a metacognitive mapping tool (MMT) supporting the college students' metacognitive learning abilities. The participants of this study were 25 third grade college students selected from Gazi Faculty of Education, Gazi University. The students participated in a six week qualitative study. They studied an online Database Management Course by getting support from the tool. The tool was developed on the four components of metacognitive skills which were planning, monitoring, evaluation and revision. The tool was utilized for an asynchronous web based course. The tool allowed students to plan their studies, monitor and evaluate their progress. After monitoring and evaluation, students could revise their planning and change their thinking patterns. A content analysis was carried out to examine students' interviews. The focus of the interviews was to investigate the students' perceptions and purpose of utilization. This study argues that using the tool gives the students an opportunity to choose exact content of the course and to plan the content for individual aims. The tool used in this study can assist time management and tracing of the students' personal study progress.