The ban on the application, that the government had accused of helping mobilise widespread anti-government protests in December, was lifted on Saturday night, Efe news reported, quoting official news agency IRNA.
Telegram has more than 40 million users in the country and was one of the media used toward the end of December to organise protests against rising inflation and corruption in the country.
Clashes between anti-government protesters and security forces had left at least 20 people dead, while more than a thousand were arrested.
Instagram, which is also very popular in Iran, was also temporarily blocked by the government during the protests.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)