This paper deals with The Development of Contextual Text Based Exposition Writing Teaching Materials of Class X Students in State 16 Senior High School, Medan. The method used in the development of teaching material research is the Borg and Gall models which used to develop a product. The product of the learning module that was developed was a contextual text-based exposition writing material for class X students in state 16 Senior High School, Medan. This research and development refers to the theory of teaching material development proposed by Borg and Gall. The finding shows that Teaching Materials Development of Exposition Text Writing Based on Contextual is the development of teaching materials is needed by students and teachers in the learning process. This is due to improving the quality of learning to be better and more interesting. The use of contextual text-based teaching writing materials is considered more effective than the textbooks used by students. This is evidenced by better student learning outcome that is the use of textbooks (Pretest) 70.68% with sufficient categories while the use of teaching materials for exposition text writing is based on contextual (Posttest) 81.40% with good categories. The effectiveness of teaching material based on the results of the pretest to posttest exposition text writing increased with a difference of 10.72%. Based on this, the product developed has been good and tested in improving students' ability in writing exposition texts in class X students in state 16 Senior High School, Medan.