Abstarct: The research presents a mexta-analysis on the effect of morphological awareness on vocabulary knowledge. By establishing a set of inclusion/exclusion criteria, 20 studies out of 32 that some had the effect sizes and others were calculated were selected from various master's theses, books, PhD dissertations, and articles published in English between 2014 and 2023. Five moderator variables were identified: participants' age, gender, language level, educational level, and publication type. According to Plonsky and Oswald’s (2014) scale, the overall effect size was found to be g = 0.89, indicating a strong and significant positive effect of morphological awareness on vocabulary knowledge. Moreover, we review and calculate the effect sizes of each study’s moderator variables and found that morphological awareness has the most significant impact on intermediate level and on teenagers aged between 10 to 18. Additionally, we presented a symmetrical funnel plot and conducted a fail-safe N test to assess whether publication bias affected our results. The findings offer clear recommendations for researchers, teachers, and material developers.