Andi Tenrisanna Syam, Dewi Furwana. A comparison between the use of mistake buster technique and online grammar … 364 A comparison between the use of mistake buster technique and online grammar instruction in teaching grammar Andi Tenrisanna Syam State Islamic Institute of Palopo Dewi Furwana State Islamic Institute of Palopo Corresponding e-mail: risannasyam23@gmail.com Abstract: This research aimed at finding out the technique which was more effective in improving students’ grammar achievement, mistake buster technique or online grammar instruction. The research employed a quasi-experimental research method. The sample consisted of 30 students. The technique of taking sampling was cluster random sampling. The research data were collected by using a grammar test to see the students’ grammar mastery and the data were analyzed by using inferential statistics through SPSS 17.0. The research result indicated that the use of online grammar instruction was more effective than mistake buster technique in improving grammar mastery of the third semester students of State Islamic Institute of Palopo in academic year 2017/2018. It was proven by the students’ posttest mean score for online grammar instruction group is higher than the students’ posttest mean score for mistake buster technique group (69.96 > 51.30). The difference of those mean score was statistically significant; it was based on t-test value, the probability value is lower than significant level (0.00 < 0.05). Based on the researchers’ observation, the students in online grammar instruction group have been more active and fun rather than the students in mistake buster technique group. Keywords: Mistake Buster Technique, Online Grammar Instruction, Teaching Grammar Introduction Mastering grammar is an important part in language learning. If we do not have good knowledge of grammar, we will surely make a lot of mistakes in speaking or in writing and we cannot communicate well. In language learning, native speakers and non–native speakers are different. When the native speakers study grammar, they usually become involved not in basic framework that they know, but in problems of variant usage like dialect differences of styles and artistic effects. In contrast with this, a non- native speaker who is learning a foreign language does not know how it’s structured. He needs to acquire this basic framework in order to master the production and the comprehension of the typical sentences of the language. Yet, he and those people who teach him often forget this fact and proceed with teaching and learning the foreign language as if it were the native language; he takes up matters of variant usage, looks sight of the central structure, and ignores its importance and difficulties. As non-native speakers, Indonesian students have difficulties in learning English grammar. Specifically, based on the researchers’ interview with the lecturer of State Islamic Institute of Palopo, the students’ grammar mastery is generally still low. One of the indicators is many wrong answers when students are given grammar tests. This problem comes to surface because of some cases. Among of them is students that do not have background knowledge about the lesson given. Lecturers just explain grammar to students directly followed by answering the questions without having discussion first and providing visual aid to students. In addition, students do not know when such grammar should be used and how their application is in daily life. Therefore, to make the English teaching in Indonesia successful, it is necessary to create new penetration and strategies in order to support and improve the quality of the education. Besides, English lecturers should create enjoyable, relaxed, and comfortable atmosphere in the classroom. However, these are essential problems that must