The right to form political parties is considered a crucial component of organized political participation and a fundamental pillar of democratic systems. By organizing social demands, cultivating political elites, presenting governance platforms, and fostering an environment for political competition, political parties play a pivotal role in ensuring free and fair elections. In contemporary legal systems, the relationship between party politics and elections serves as a key indicator for assessing the quality of democracy and the efficacy of the political system. However, Iran's historical experience reveals that the right to form parties has consistently faced structural, legal, and institutional challenges, which have in turn impacted the quality of electoral competition. This study, titled "Challenges to the Right to Form Political Parties in the Constitutional and Islamic Republic Eras: A Focus on Free and Fair Elections," examines the legal and institutional developments regarding political parties and their role in the electoral process. The primary objective is to analyze the status of this right within Iran's legal system and to elucidate its impact on meeting the standards for free and fair elections. To this end, the study reviews the theoretical foundations of the right to form parties in international human rights instruments and examines the status of this right across two pivotal periods in Iran's political history: