The purpose of this research is to find out the effectiveness of applying information gap in teaching and learning speaking for the eight grade students of junior high school. The writer used an experimental method. The population of this research was the students of MTS N. 8 Duri Kosambi West Jakarta. The samples were from 1 class of fifth classes which was taken random. The writer took 20 students from the one class chosen randomly. The result of this research shows that using information gap in teaching and learning speaking is getting an improvement or progress of the students? skill in class. The result is tobserved = 2,89 and ttable = 1,68. Because to > tt, it means that there is a significant progress in expressing their ideas by oral form and the students? speaking abilities in accuracy, fluency and comprehensibility. The research result is hoped to be useful for the students to make them improving their ability in speaking activity, like expressing their ideas and opinion, sharing their experiences and many more. In addition, it gives information to the teachers to know the models of conversation or dialogue with creating language function which is very authentic and realistic topic which relate to the students? life, so it will make the situation of English learning become alive and effective.