Task-based learning is an authentic learning strategy in which students plan, implement, and evaluate Tasks that have real-world applications beyond the classrooms, this strategy is very suitable to use in speaking class. The purpose of this study is to discover whether Task Based Learning strategy improved students’ speaking ability. The method used in this research is an experimental. The data collection process was carried out by doing pre-test and post-test. the sample in this study were 36 students of SMAN 1 Banda Aceh. This research was conducted to attain the information about the improvement of the students’ speaking ability through Task Based Learning strategy. The result of the test shows that the mean score of pre-test is 64 while in the post-test is 70. It proved that the mean score of both are very different. Moreover, based on the analysis of hypothesis showed that T-test> T-table (11.42 > 2,7). Therefore, it can be concluded that teaching by using Task based learning (TBL) method can improve the students’ speaking ability.