This research paper presents a meta-analysis conducted to examine the relationship between board size and Return on Assets (ROA) as a measure of firm performance. A total of 124 research papers were selected for the meta-analysis, and the “Metafor” package in R-programming was used for data analysis. The findings revealed that board size is a common factor in most studies and has a significant impact on firm performance. Among the selected papers, eight studies were found to have a correlation value between ROA and board size. The meta-analysis results indicated that there is no statistically significant difference between board size and ROA at a 95% confidence level. Heterogeneity was observed among the studies, suggesting variations in the effect size. Overall, this study contributes to the understanding of the relationship between board size and firm performance.