Abstract

Truthfulness in advertising has long been recognized as a fundamental requirement for ensuring fair competition, protecting consumers, and maintaining public trust in the market economy. Beyond its positive legal formulation in national legal systems, the obligation of truthful advertising reflects a deeper ethical–legal norm that transcends jurisdictional boundaries. This article examines the duty of truthfulness in advertising as a universal ethical–legal standard, drawing on moral philosophy, natural law theory, consumer protection theory, and modern regulatory approaches. The study argues that truthful advertising is not merely a technical legal requirement but a normative principle rooted in human dignity, informational justice, and social responsibility. By analyzing the evolution from moral obligation to legally enforceable duty, the article highlights the universal nature of truthfulness in advertising and explores its implications for contemporary advertising regulation, particularly in the digital age. The article has established that many businesses disseminate deceptive advertisements across traditional media channels and digital platforms, thereby undermining customer trust and loyalty. The three jurisdictions analyzed, the United States, the UK, and Vietnam, have regulations and laws prohibiting deceptive advertising.