The title of this research is ”An Analysis of Students' Ability in Using Passive Voice at the Third Grade Students of MAS Kepenuhan” this research was conducted at MAS Kepenuhan of Rokan Hulu Regency to the third grade students. Number of the samples were chosen as the participant of this research were 26 students. In this research, the researcher wanted to see the students' ability in using passive voice and also their difficulties in learning it. The purpose of the research are to describe students' ability and students' difficulty in using passive voice in simple present and simple past, the researcher gave a written test which was consist of 30 test items. There were 15 items of passive voice in simple present tense and there were 15 items of passive voice of simple past tense. Meanwhile, to find out students' difficulties in learning passive voice, the researcher interviewed students. Based on the test result, the researcher found that students' ability in using passive voice due to their score on the test given was 85 and it can be classified in the excellent level. For the use of passive voice in simple present tense, the researcher found that the average students' score was 84 and it can be classified in the good level and in the passive voice of simple past tense the students' average score was 84 and it can be classified as the good level. From the result of interview, the researcher found that most of the students' difficulties in learning passive voice was in the mastering of past participle.