This current research aims to improve students’ self-efficacy in speaking English by carrying out brainstorming technique. Therefore, Classroom Action Research (CAR) was applied to gain that aim. The researcher used the observation sheet of teacher activities, student activities, questionnaire, and documentation as her technique of collecting data. The objects in this research were eleventh-grade students at Madrasah Aliyah Negeri 2 Kabupaten Gorontalo academic year 2022–2023, totaling 17 students included 12 female and 5 male students. The English teacher decided the minimum mastery criteria are 75. Base on the observation of the pre-cycle, students attained 43.23 in average. In the first cycle, after the brainstorming was carried out, students achieved 57.94, while in the second cycle increased to 76.17. The result showed that brainstorming technique was successful to improve students’ self efficacy in speaking English.