With the rapid expansion of digitalization, brands are increasingly pressured to enhance their environmental responsibilities. Green marketing and advertising strategies play a significant role in promoting eco-friendly practices aligned with sustainability principles. Social media has emerged as a vital platform for brands to directly communicate their environmental efforts to consumers and reach broader audiences. However, claims not based on genuinely sustainable practices may result in misleading actions known as “greenwashing,” which can erode consumer trust. In this context, greenwashing refers to brands attempting to create a false impression of being environmentally friendly, leading to misconceptions that can quickly spread through social media. This study highlights that the ethical and trustworthy foundation of sustainable marketing must be grounded in the actual environmental performance of brands; otherwise, potential damage to brand reputation may arise.