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This meta-analysis was conducted to synthesize the effect of 22 primary studies which have been conducted to test the effect of the integrated skills approach (ISA) on language skills and components. Three questions guide this analyses: What is the overall effect of ISA  on language skills and sub-skills? To what extent moderator variables such as learners level of education and proficiency modify the effect of  the ISA?  What is the magnitude of publication bias in this analysis? The overall effect size was found to be 1.18, which  represents a  large effect size based on Cohen, Manion and Morrison’ (2007) scale. The results of moderator analysis revealed that the ISA has the largest effect for advanced learners and at a tertiary level of education. The symmetrical funnel plot together with fail-safe N test shows that publication bias does not have any significant effect on the effect size reported in this study. The findings of this meta-analysis have clear implications for practitioners, policymakers, and curriculum developers.