The purpose of this study was to assess the effectiveness of timetable scheduling that was developed using graph coloring for the class period time tabling. This study presents a study of using graph coloring for effective timetable scheduling at ordinary secondary level, a case study of Dodoma central secondary school in Dodoma city. Algorithms for timetable scheduling using graph coloring were developed, the training for academic teachers on how to design a class periods timetable using graph coloring was offered, and the developed class timetable through teachers' opinions on the effectiveness of the new timetable was assessed. It was found that the new timetable was effective because it eliminated collisions among teachers while using the timetable. This finding has implications on teaching and learning process by using an effective timetable preparation and implementation.