Mergers and acquisitions (M&A) are an important corporate restructuring strategy used for firm growth. This is evident with the number of M&A deals undertaken globally. One important aspect which the researchers investigate is how the stock market reacts to the M&A decisions and what impact does it bring to the shareholders. A widely used methodology to examine this impact is event study which measures the impact of M&A announcement on the stock prices. Event study is a short-term performance evaluation method applied to understand the abnormal returns in the event window post-M&A. This aim of this study is to understand the market reaction to the M&A decisions in prior research. A review of existing literature on M&A and event studies has been conducted in this study. This research synthesises the key findings from the empirical studies focused on event study and provides a comprehensive perspective of the different market reactions on M&A decisions. The stock market's response to M&A announcements varies greatly, and the initial gains are frequently short term based on empirical examination. The outcomes are significantly influenced by the payment method and geographic context, highlighting the necessity of thorough assessment of these factors by the stakeholders involved, particularly in emerging markets. This study may provide crucial policy implications to the top management for making strategic choices and choosing the ideal target for the M&A deals.