The Iranian opposition consists of various political groups, movements and people who oppose and seek the overthrow of the government of the Islamic Republic and its system of theocratic clerical rule based on the doctrine of the Guardianship of the Islamic Jurist (Velayat-e Faqih).

The opposition to Iran's theocratic government is ideologically diverse and includes republicans, monarchists, secularists, nationalists, liberals, and communists. In addition to secular and nationalist currents, Islamist groups and dissident Shia clerics have criticised aspects of the Islamic Republic and its political structure, though most are part of the Iranian reformists, certain Sunni Islamist and Kurdish Islamist movements have also opposed the state for religious or political reasons.

Opposition activity occurs both inside Iran and among the Iranian diaspora. Within Iran, political opposition is highly repressed by the government, and many opposition organisations and figures operate abroad. Protests organized by the opposition were violently suppressed, and many opposition figures, such as Mir Hossein Mousavi and Zahra Rahnavard, were held under house arrest for years without any charges. Thousands of political opponents of the Iranian government were summarily executed in 1988. Since the start of the 2025-2026 protests, Iranian government has been carrying out executions on almost daily basis. Analysts and activists debate the mechanism of transition, whether change is more likely to emerge from within existing structures, mass civil resistance, elite fragmentation, or abrupt systemic collapse.

The issue of foreign intervention remains contested while some perspectives emphasise diplomatic pressure, sanctions, and international support for human rights as necessary tools to weaken authoritarian structures. Others warn that overt external intervention, especially military involvement, could undermine legitimacy, provoke nationalist backlash, or destabilise the region further.

These debates are reflected in the diversity of opposition actors. For example, the National Council of Resistance of Iran (NCRI) has outlined a Ten-Point Plan proposing a structured, rights-based democratic framework. Reza Pahlavi, Iran's exiled crown prince, has advocated for a secular democratic system to be determined through a national referendum rather than the restoration of monarchy as a predetermined outcome. His proposals emphasise national unity, human rights protections, and the establishment of a transitional framework involving a temporary governing body, free elections, and the drafting of a new constitution. He has also supported international pressure on the current regime while opposing foreign military intervention, arguing that legitimacy must come from within Iranian society.

Periodic nationwide protests have challenged the authorities, including the 1999 student protests, the 2009 Green Movement and 2009 protests following disputed presidential elections, the 2017–2018 and 2019–2020 protests, the 2022–2023 protests that followed the death of Mahsa Amini in police custody, and the 2025–2026 protests, which have been the largest unrest since the 1979 Revolution. These movements often articulate demands that extend beyond formal political change, calling for broader cultural transformation, personal freedoms, and social justice. In this sense, democratisation is framed not only as a political project but also as a societal one, involving shifts in norms surrounding gender, authority, and individual rights. These demonstrations were met with large-scale security crackdowns, resulting in tens of thousands of deaths, injuries, and arrests.

Following the Islamic Revolution of 1979 and the establishment of the Islamic Republic, opposition to the new political order soon emerged. On 8 March 1979, coinciding with International Women's Day, thousands of women and supporters demonstrated in Tehran and other cities against proposals by the new authorities to enforce compulsory Islamic dress for women in public. The demonstrations continued for several days and became one of the earliest large-scale public protests against policies introduced by the post-revolutionary government.

On 14 June 1980, Ruhollah Khomeini called for the "Islamisation" of universities and the removal of what he described as Western and secular influences from Iran's higher education system. This directive led to the Iranian Cultural Revolution, during which universities were closed from 1980 to 1983 while curricula were revised and academic staff and students were screened for ideological conformity. During this period, numerous academics, students, and administrators were dismissed or prevented from continuing their studies or employment on political or religious grounds.