The present study aimed at investigating the effect of a brain- based learning strategy on developing some first grade secondary stage students' EFL critical writing   skills and self- regulation. The study adopted the quasi-experimental design. Participants of the study were (sixty) first year, secondary institute students from Sharqiat Mubasher secondary institute for girls, Al Ibrahemia, Al Sharqia Governorate, Egypt. They were divided into a control group (n=30) and an experimental (n=30).The experimental group was taught the prescribed EFL student book (New Hello! English for secondary schools year 1) through the brain- based learning strategy, whereas, the control group was taught the same book using regular instruction. To achieve the aim of the study, the researcher designed a questionnaire for determining the target critical writing skills and a scale for determining the most important self- regulation dimensions. Based on these critical writing skills and self- regulation dimensions, a pre-post critical writing test and a scale were designed.Then, the data were treated statistically. The findings of the study revealed that the brain- based learning strategy had a positive effect on developing first year secondary institute students' EFL critical writing skills and self- regulation.