This study investigated the effect of Design Thinking on developing the secondary stage students' EFL writing performance. A randomly selected group of the secondary stage students (N=14) in Al Borg Governmental School in Al Khanka, Qalyubia Governorate, Egypt, in the academic year 2021/2022 were trained through a proposed program based on using Design Thinking for developing writing performance. The design of the present study was based on the one-group, mixed research design. A pre-posttest was designed and administered to the group before and after the implementation of the proposed program. The test aimed to determine to what extent the Design Thinking Approach helped the secondary stage students to master their writing performance. The researcher designed a nine week program, the pre/posttest, the rubric, and the participants' questionnaire. The nine-week intensive English language program was three sessions a week, to boost their writing performance. The obtained data was statistically analyzed using Wilcoxon Test, and the effect size factor as well as qualitatively analyzed through the rubric. Both the quantitative and qualitative analysis revealed that design thinking has an effective influence on promoting EFL secondary stage writing performance.