ABSTRACTrnThis Thesis is entitled “A STUDY ON VOCABULARY MASTERY OFrnTHE ELEVENTH GRADE STUDENTS OF SMA MUHAMMADIYAHrnKUPANG IN SCHOOL YEAR 2012/2013’’.This study was conducted in order tornanswer the following questions: (1) Do the elevent grade students SMArnMuhammadiyah Kupang able to master the English Vocabulary? (2) What is theirrnlevel of mastery of English Vocabulary? The main objectives of this study arernmentioned: (1) To find out whether the students of SMA M uhammadiyah Kupangrnare able to master the English vocabulary. (2) To know the mastery level of therneleventh grade students of SMA Muhammadiyah Kupang on vocabulary. Therninstrument that the writer used for gathering the data was the test. The testrnconsisted of fourty (40) test items, divided into two types namely: 30 test items wasrnAnswer the questions based on the picture, into a bad room in modern house labelrn10 things.The result of the data analysis shows that (1) the eleventh grade studentsrnof SMA Muhammadiyah Kupang do not master vocabulary using by picture.rn(2).The mastery level of eleventh grade students of SMA Muhammadiyah Kupangrnwas” Poor” (44.62).Based on the result, so the writer would like to suggest to:rnfirstly to the teachers must teach students to master vocabulary by using picturesrnand teachers should provide more pictures to the students so that students canrnmaster vocabulary correctly. Secondly students should be able mastery vocabularyrnthrough images correctly and students need to know the names of the images in the