Prior researches have established the significant importance of metacognitive knowledge in enhancing learner autonomy and empowering him to achieve optimal success in EFL learning in general and in EFL writing in particular. Using a correlation analysis, this study sought to investigate the relationship between readiness for autonomy, metacognitive knowledge, and proficiency level of Algerian ENSB students (N=125) in EFL writing. To estimate the relationship between readiness for autonomy and metacognitive knowledge variables, a regression analysis is conducted. The results of the correlation analysis demonstrated a weak and significant correlation between metacognitive knowledge and proficiency level and a very week and significant correlation between readiness for autonomy and proficiency level. However, a strong and significant correlation was revealed between readiness for autonomy and metacognitive knowledge. Additionally, the regression analysis indicated that ENSB students’ metacognitive knowledge contributes significantly in predicting their readiness for autonomy variable. Based on these findings, it is suggested that ENSB students’ metacognitive knowledge is strongly related to their readiness for autonomous learning. Thus, it is recommended that EFL writing teachers should raise their students ‘metacognitive knowledge base to enhance their readiness for autonomous learning. Keywords: metacognitive knowledge, readiness for autonomy, proficiency level, EFL writing.