This chapter explores the concept of psychological manipulation in the context of consumer behaviour, focusing on the dark patterns in digital and online environments. Dark patterns are defined as a set of deceptive user interface designs and behavioural techniques that make people do things they would not otherwise do, which undermines their autonomy. It surveys the cognitive mechanisms of such manipulations—which include the use of cognitive biases, social influence tactics, and persuasive technology, continually for effects on consumer decision-making. In this chapter, by giving a critical review of related literature and some cases, the ethical implications of dark patterns will be outlined. Additionally, the chapter highlights how such manipulative tactics destroy consumer autonomy by influencing decisions that often lead to unintended consequences. It further talks about the role of digital platforms and companies in reinforcing these patterns, focusing on regulatory frameworks that could help mitigate their negative impact. The chapter synthesises insights from psychology, behavioural economics, and digital marketing to provide a comprehensive understanding of how dark patterns exploit human psychology to limit consumer freedom and autonomy. The conclusion reflects that consumer education, policy development, and ethical design practices may hold a key to offsetting the growing prevalence of these manipulative techniques.