The rapid growth of e-commerce has transformed consumer markets, but alongside convenience has emerged the troubling phenomenon of “dark patterns” deceptive user interface designs that manipulate consumer decision-making. These patterns exploit cognitive biases, nudge users into unintended purchases or subscriptions, and erode consumer autonomy. This paper undertakes a comparative legal and psychological analysis of dark patterns, examining their prevalence, the vulnerabilities they exploit, and the effectiveness of regulatory responses. Drawing on legal frameworks in the United States, European Union, and India, it explores how consumer protection and data privacy laws have attempted to counter manipulative practices. Parallelly, insights from behavioural psychology demonstrate how heuristics such as scarcity bias, default bias, and loss aversion are systematically weaponized in digital marketplaces. While legal measures exist, enforcement is fragmented and often lags behind evolving technological designs. Psychological studies suggest that consumer awareness alone is insufficient, as manipulative designs operate subconsciously. The paper argues that safeguarding digital consumers requires a dual strategy—strengthening legal standards and incorporating behavioural insights into regulatory design. By bridging law and psychology, this study highlights pathways for more ethical e-commerce practices and proposes measures for policymakers, businesses, and consumer advocates to curb the proliferation of dark patterns.