This study aimed to identify the effect of using brainstorming in the development of creative thinking and achievement in the English language among 10th grade students at King Abdullah II School of Excellence. The study sample consisted of (168) students. The problem of the study was to answer the main question: What is the impact of using brainstorming strategy in the development of creative thinking and achievement in English language of 10th grade students at King Abdullah II School of Excellence in Amman? To answer this question and the sub questions, the researcher built the study tools, which were: 1) A test for creative thinking in English, prepared by the researcher. 2) Achievement test of English language prepared by the researcher and consisted of (30) multiple choice questions. The validity and reliability of the tools were verified. The researcher used the semi-experimental method according to the nature of the study. The researcher applied the pre and post study tools to the two groups (experimental and control), Where the students of the control group were taught using the normal way, while the experimental group was taught using the brainstorming strategy. The study was conducted in the second semester of the academic year 2017/2018. The results of the study showed that there were statistically significant differences at (a=0.05) between the mean scores of the experimental group (taught using the brainstorming strategy) and the control group (taught in the usual way) in the pre/posttest of creative thinking. Results also showed there were statistically significant differences at (a=0.05) between the mean scores of the experimental group (taught using the brainstorming strategy) and the control group (taught in the usual way) in each skill of creative thinking (fluency, flexibility, and originality) in the pre/posttest of creative thinking. And also there were statistically significant differences at (a=0.05) between the mean scores of the experimental group and the control group in the achievement test of English language. In light of the results of the study, the researcher proposed some recommendations such as: English language books in the educational stages should include some creative thinking skills, such as fluency, flexibility and originality, and the use of modern methods and strategies in teaching English in different educational stages, such as the use of brainstorming.