The country has blocked access to the internet giant's search engine and Gmail services following the controversy surrounding an anti-Islamic film posted on Google-owned video network YouTube.
A government minister made the announcement via a television broadcast yesterday evening (September 23), and a public text message was sent out as a reminder, BBC News reports.
"Google and Gmail will be filtered nationwide, and will remain filtered until further notice," said an adviser to Iran's public prosecutor's office Abdul Samad Khoramabadi.
The anti-Islamic film, which is seen as mocking the Prophet Muhammad, sparked protests in Egypt, Libya and the Iranian capital Tehran. YouTube has refused to remove the clip in numerous territories, claiming it does not violate any of its policies.
Google joins a long list of other Western websites blocked by a firewall in the territory. An uncensored version of the search engine, which the Iranian authorities monitor closely, remains in operation.
This is not the first time that Google has been censored in Iran. The country restricted access to its search engine and email service ahead of its parliamentary elections in March.