Abstrak
Vocabulary is an important thing in English. Therefore, at university vocabulary is a compulsory subject for English language study program. Students cannot speak, write, listen, and read the reading texts when they do not have enough vocabulary to understand the reading texts. Thus, students should master vocabulary. The purpose of this research is to know students’ problems in vocabulary mastery. This research is a descriptive research. The population of the research is students of education faculty of UPI YPTK Padang in 2018/2019 academic year. The sample of the research is students of English education language study program. The data were collected by using questionnaire. Questionnaire is given to know students’ reasons and problems in mastery vocabulary. The result of the questionnaire proved that students have different opinions about their ability in mastery vocabulary.