The increasing popularity of electronic cigarettes (e-cigarettes) has become a significant public health concern. Recent data show not only a growing number of users, especially among young adults, but also a notable expansion of the global e-cigarette market. E-cigarettes are often perceived as a less harmful alternative to traditional smoking, and although they do contain fewer toxic substances, their long-term health effects are still not fully understood. At the same time, obesity rates are rising worldwide and have become one of the leading preventable causes of chronic diseases. Nicotine, the main active substance in both conventional cigarettes and e-cigarettes, may play a role in body weight regulation. Its known effects include appetite suppression and an increase in the resting metabolic rate. Consequently, some individuals may use e-cigarettes as a tool to manage weight, particularly after quitting smoking. However, combustible cigarettes, nicotine itself, and e-cigarettes are not recommended for the treatment or prevention of obesity, and they should not be used as a strategy for intentional weight reduction. This review aims to summarise the current state of knowledge on the relationship between e-cigarette use and body mass. We discuss both physiological mechanisms related to nicotine as well as behavioural aspects that might influence food intake and weight control. Given the increasing prevalence of both vaping and obesity, understanding the potential links between the two is important from both a clinical and public health perspective.