Abstract: The aim of the current study is to investigate the effect of a suggested model RW based on constructivism on Palestinian EFL secondary school students' writing skill performance. The sample consisted of (87) female students divided into two groups; a control group 43 and an experimental group 44 students. The researchers used quasi-experimental design of two purposefully assigned, randomly-chosen groups with pre and post tests for each. Different statistical tests included in the Statistical Package for the Social Sciences (SPSS) were used to analyze the data collected while answering the study questions and testing the hypotheses. The results showed that there were statistically significant differences at (? ? 0.05) between the experimental group and the control group in relation to the writing skills in favor of the former. Also, the effect size of using the model based on constructivism was significantly large on students' writing skills. The researcher strongly recommended using the suggested model RW in teaching writing skill for the EFL secondary school students.