In 30 countries, heads of state must belong to a certain religion

Bhutan

As reported by the Pew Research Center 30 countries in the world require their heads of state to have a particular religious affiliation, they must belong to a particular religious group.ii

Two countries, Bhutan and Thailand (both monarchies), require their head of state to be Buddhist. While in Burma the president is ‘prohibited form being a member of a religious order’.

There are other interesting findings:

‘More than half of the countries with religion-related restrictions on their heads of state (17) maintain that the office must be held by a Muslim. In Jordan, for example, the heir to the throne must be a Muslim child of Muslim parents. In Tunisia, any Muslim male or female voter born in the country may qualify as a candidate for president. Malaysia, Pakistan and Mauritania also restrict their heads of state to Muslim citizens.’

While ceremonial religious duties are required in other countries:

In addition to the 30 countries in this analysis, another 19 nations have religious requirements for ceremonial monarchs who serve as their heads of state. Sixteen of these, including the United Kingdom, Australia, Canada and New Zealand, are members of the Commonwealth of Nations with Queen Elizabeth II – also known as the Defender of the Faith – as their head of state. The other countries in this category are Denmark, Norway and Sweden.’

FT_Religious_Requirements