With the rapid expansion of communication technologies and the growing influence of cyberspace, online service providers have become key players in economic and social domains. This transformation, alongside its numerous opportunities, has raised significant legal challenges, among which determining the scope and limits of civil liability of online service providers towards users and third parties is of utmost importance. The central research question of this study is how civil liability of such providers is defined and limited under Iranian law, and what similarities or differences exist in comparison with other legal systems. The importance of this inquiry lies in the fact that, in today’s digital world, material and moral damages caused by online activities can spread rapidly and extensively, and the absence of clear regulations in this regard may lead to violations of individual rights and gaps in compensation mechanisms. The aim of this article is to analyze the existing legal framework in Iran and, through a comparative approach, examine international regulations and the laws of advanced jurisdictions, thereby proposing solutions for improving the domestic legal system. The research method is descriptive-analytical and based on documentary studies, including legal texts, statutes, and judicial precedents. The findings indicate that, although Iranian law provides general principles on civil liability, it lacks specific and explicit provisions concerning the liability of online service providers. In contrast, in advanced legal systems such as those of the European Union and the United States, detailed rules on limited liability, safe harbor provisions, and statutory exceptions have been established. The novelty of this research lies in its comparative perspective, which highlights the deficiencies of the Iranian system and offers recommendations for strengthening its legal framework.