It is estimated that 99.4% (July 2016 est.) of the Iranian population identify as Muslim – the majority being Shi’a (also known as Shi’ite) Muslims.1 Iran is the only Muslim country to declare itself officially Shi’ite. A minority of around 5-10% of the population identify as Sunni Muslims. Within the Shi’a branch of Islam, there are different sects. The biggest is the Twelver Shi’a sect; however, some Iranians are also Ismaili Shi’a Muslims.