In their rally, students from different universities in Tehran chanted slogans against Egyptian President Hosni Mubarak, and called for Muslim unity.
Students also announced their support for the revolution in Tunis.
Anti-government protests continue across Egypt for the fifth consecutive day despite the deployment of army forces and tanks. The curfew has been extended in the capital city as well as in Suez and Alexandria.
Protesters are calling on troops to come over to their side.
At least 100 people have been killed and around 2,000 others have been wounded since protests began on Tuesday.
Egypt's main opposition movement, the Muslim Brotherhood, has called for an interim government without the ruling National Democratic Party (NDP), warning that Egypt would explode if Mubarak continues to refuse to listen to the people.
Senior leader Ahmed Ezz has resigned from the ruling party due to growing differences with Mubarak.
Egyptians are calling for a regime change. They want President Mubarak to step down. The president, however, says he will not resign. He has merely sacked his cabinet and promised economic and political reforms.