The ability to think critically is a critical element in the 21st era, especially in education. The low level of students' critical thinking skills is a serious problem that must be addressed immediately because it will harm many parties if it continues. In Indonesia, there is still a need to improve in teaching critical thinking and training students because the system often emphasizes memorizing lessons and formulas, so students are less interested in thinking critically and tend to accept information without considering it first. This research aims to discover teachers' efforts to improve critical thinking in the classroom, find out the obstacles in improving critical thinking, and also to find the solution of the obstacle in improving critical thinking students’. This research uses qualitative methods and interviews as data collection techniques. The participants are three English teachers at MAS Tgk Chiek Oemar Diyan. The results of this research show that teachers' efforts to improve critical thinking include the use of learning methods that contain aspects of critical thinking, such as group discussions, problem-based learning, and scientific methods; the use of learning media that can support students' critical thinking use power-point, youtube, picture lerning; providing questions that stimulate students to think critically and providing exercises to demonstrate students' critical thinking. While improving students critical thinking, teachers experience some obstacles. There are limited references when searching for information, less motivation in learning, lack of self-confidence due to needing to speak English fluently, and limited English vocabulary. To overcome these problems, teachers use several methods: providing motivation, monitoring students to look for problems, allowing students to search for information on the internet, and requiring them to bring a dictionary.