The purpose of this study was to investigate the effect of utilizing authentic materials based on journal writing program on developing writing performance skills of EFL secondary school students. The design used in the present study was quasi-experimental. Two classes were randomly drawn from one of Zagazig secondary schools, namely Zagazig Experimental Language Secondary  School for Girls in the school year 2015/2016.The sample of the study consisted of 46 first grade students randomly distributed to two groups, the experimental group and the control one of 23 students each. The experimental group received researcher-facilitated activities through Authentic Materials based on Journal Writing program for teaching writing performance skills. To achieve the objectives of the study, a checklist of writing performance skills was prepared, a proposed program was developed. Based on the writing performance skills judged valid, a test was developed and administered to the two groups and a rubric for correction was developed. The experiment lasted for three months. Upon the completion of the experiment, all students were post-tested. Differences between the pretests and posttests were calculated using t-test. Results indicated that (1) there was a statistically significant difference between the mean scores of the experimental group students in their performance in the pre and post application of the writing performance test, (2) there was a statistically significant difference between the mean scores of the experimental group and the control group in their performance in the post application of the writing tests in favor of the experimental group. It was concluded that the present study provided evidence for the effectiveness of utilizing Authentic Materials based on Journal Writing program in developing the experimental group students' writing performance skills.