The current study investigated the effect of a program based on writer's workshop (WWS) on developing secondary stage students' argumentative writing and reduces their writing apprehension. Study participants included 68 college students. The intact classes were randomized from first-year secondary students at Om Khnan secondary school, Quesna, Menoufia governorate during the first semester of the 2021-2022 scholastic year. They were divided into two groups; experimental (34) and control (34).The study adopted the quasi-experimental preposttest design. The instruments of the research included an EFL argumentative writing skills test, and the Daly-Miller Writing Apprehension Test (WAT). The findings revealed that using writer's workshop had a positive effect on developing EFL secondary stage students' argumentative writing skills and reducing their writing apprehension. Hence, the results seemed to provide adequate evidence to support the hypotheses. The progress that occurred in the students' argumentative writing skills was due to WWS. Also, students' writing apprehension was decreased. It is recommended that teachers and curriculum designers pay attention to the importance of writer's workshop in EFL teaching and learning.