The Efficient Market Hypothesis (EMH) has long been a cornerstone in financial theory, asserting that stock prices fully reflect all available information, leading to an efficient market where no investor can consistently achieve returns higher than the market average. However, recent critiques, including those from Malkiel (2017) and Audu et al. (2022), have challenged the validity of EMH, particularly in the wake of market crises where the theory’s assumptions have been questioned. These detractors argue that the failure of EMH to predict or prevent market downturns indicates that capital markets are not as efficient as the hypothesis suggests.This paper delves into the ongoing debate over the efficiency of stock markets, examining both the theoretical framework of EMH and its practical implications. While EMH posits that stock prices are always accurately priced based on available information—whether public or private—critics assert that factors such as transaction costs, unequal access to information, and investor biases undermine the theory's assumptions. The role of these challenges is highlighted through examples of market inefficiencies and investor behaviors that contradict the expectations set by EMH.Through a review of existing literature and analysis of empirical data, this study investigates whether stock markets can truly be considered efficient or if they are subject to irrational behaviors and external factors that prevent the ideal functioning of an efficient market. The findings suggest that while EMH may hold under certain conditions, real-world markets often display inefficiencies due to imperfect information distribution, transaction costs, and human psychological biases, which complicate the assumptions of the hypothesis.This paper contributes to the ongoing discourse by proposing a more nuanced understanding of market efficiency that accounts for these practical deviations from the idealized model, offering insights for investors and policymakers seeking to navigate the complexities of financial markets.