Abstract: Students demotivation is a study which is rarely to be researched. Demotivation is decreasing the basis of motivation. It is caused by students do not motive to do something and to fulfill a specific activity. One of the reasons of students demotivation in speaking English is teaching speaking. The purpose of this study was to describe the biggest demotivating factors on students speaking of the fourth-year students of English Education Study Program of Muhammadiyah Kotabumi University. The research method used in this study is descriptive quantitative method. The data from this study were taken from the results of questionnaire. The results of this study is the biggest demotivating factors on students speaking are lack of self-confidence to speak English in classroom with 100% of students who chose this statement. Secondly, expecting to use (or speak and write) grammatically correct English with 96% of students who chose this statement. Lastly, the lecturer assign to read a great number of textbooks and supplementary readers with 92% of students who chose this statement. It is very important for the lecturer and students to know these demotivating factors due to improve students speaking English skill.