Iran does not confer any recognition to dual nationality and considers dual citizens to be Iranian citizens only. More to the point and noteworthy specially in relation to high profile people (politicians, celebrities and other citizens going public in active opposition to the Iranian Establishment ), being a dual national of certain states (basically the United States and some West European states) could currently prove to be a headache and a potential source of close attention (euphemism in order not to say “watch” and “vigilance”) on the part of the Iranian state security apparatus to the point that dual nationality of such particular people could be actually be weaponized against them in the course of any judicial action that their proactive opposition to the Iranian government could give rise to and they ( basically people wanted or otherwise on the radar screen and watch list of the Iranian security apparatus) may be at greater risk of arrest or detention than other citizens in circumstances allegedly not in total compliance with due process of law or described by themselves as such after their release (release which often intervenes after protracted negotiation and purportedly within a “package” involving an exchange deal) and arrival in their second passport country (basically the United States and in some cases certain EU states). In other terms, Iranian authorities treat dual nationals as Iranian nationals and systematically turn down requests made by other governments on their behalf for exercise of such rights as consular visits. Within this general framework, Iranian nationals are required to present their Iranian passport to enter and leave Iran.
These restrictions are, however, far from dampening the exponential rise in demand by Iranian citizens of all social segments for a second passport. Indeed, for multiple reasons basically dealing with desire to improve international mobility and greater access to opportunities in light of visa requirement imposed by no less than 147 countries on holders of Iranian passports, there has been a significant and sharp increase in the number of Iranian nationals applying for a second passport one way or another including, but not limited to, trying to meet residency requirement in the host country , buying property or setting up a business there or even going for purchase of a second passport from Caribbean island states offering outright attainment of citizenship without any need for a prior residency term or business activity in the destination country to the extent that some estimates put the current number of Iranian citizens with dual nationality at no less than 6 million (out of a total population of 86 million). However, this figure is to be treated with care and caution as it is likely to include also Iranian citizens residing abroad without having passports of their host countries (essentially holders of US Green Card and Canadian permanent residency card).
More precisely, it is virtually through an argumentum ex contrario or construction or interpretation from the contrary of provisions of Art. 977 of the Iranian Civil Code (in elaboration of paragraphs 4 and 5 of Art. 976 ibid which discuss situation of Iranian minors with multiple citizenship) dealing with multiple citizenship that there is no penalization of dual nationality but rather, its toleration to exist in symbiosis with Iranian nationality.
As to main features of the Iranian nationality law, it can be described as containing principles of both jus sanguinis and jus soli.
The full nationality law is defined in Book 2 of the Civil Code of Iran, Articles 976 through 991.
To begin with, Article 976 of the Civil Code of Iran defines who is an Iranian national as follows:
Nota bene: Provisions of Paragraphs 4 and 5 above do not apply to children born to foreign consular and diplomatic agents (unquote)
Notwithstanding the foregoing preponderance of paternal lineage to determine nationality, it is to be noted that in certain well defined circumstances, nationality can also transcend through the mother. Indeed, a new policy allowing Iranian women to pass down their citizenship to their children born inside Iran and believed to be applicable to no less than 30,000 Iranian women united (often in sharia type) marriage to basically Afghan guest workers was introduced as amendment to the law of 24 September 2006 on “Determining the Nationality of Children Born from a Marriage of Iranian Women and Foreign Men” was introduced through a Single Act whereby children born from a sharia marriage of Iranian women and non-Iranian men, who have been born before or will be born after the adoption of this law, before they reach the full age of 18 - based on the solar calendar - at the request of their Iranian mother shall be granted Iranian nationality if they had a clean police record . The aforementioned children, upon reaching the full age of 18 based on the solar calendar, in the absence of their Iranian mothers’ request, may apply for Iranian nationality and if they had no record of breach of security, they shall be granted Iranian nationality.
The results of the security checks must be provided within three months and the Police Force is obligated to act for the issuance of a residence permit for the non-Iranian father if he had no security violations background (determined by the Security Apparatus).
Nota Bene 1 – In case the applicant’s father or mother is not alive or accessible, where there is a doubt on the proof of lineage, a competent court shall ascertain the lineage.
Nota Bene 2 – Stateless persons who themselves and at least one of their parents had been born in Iran, can apply for Iranian nationality upon reaching the full age of 18 based on the solar calendar, which will be granted Iranian nationality if they had no criminal records and security violations background (determined by the security apparatus).
The aforementioned law was adopted during the open meeting of the Islamic Consultative Assembly on Tuesday 24th September 2019 and was approved by the Guardian Council on 2nd October 2019.
As to naturalization (Cf. Art. 979 ibid.), an application for naturalization as an Iranian must be submitted to either directly the Ministry of Foreign Affairs in Tehran , or through the Governors, or the Governors-General in the provinces and must contain certified copies of identity documents in relation to the applicant and his family (wife and children), certificate certifying period of residence, clean criminal record, sufficient assets and employment that ensures a livelihood.
Last but not least and on a separate but relevant note i.e. regarding deprivation of Iranian nationality, it is not applied as a penalty. However, voluntary renunciation of Iranian citizenship is possible, in theory (for persons over the age of 25 with this caveat that for males, absence off military service liability is a must), subject to approval by the Council of Ministers. However, this rarely occurs in practical terms for several reasons including the lengthy and tedious process involved as well as necessity for the candidates to sell off any real property they presently own or expect to come into possession of through other means such as through inheritance, gif, business transactions… not to speak of the fact that websites of many Iranian embassies have permanently removed or temporarily deactivated pages where Iranians residing abroad could file online their applications for renunciation of Iranian nationality.