The President was received at the Mehrabad International Airport by the Iranian Deputy President, Mr Shariat Mardi around 4.44pm Nigerian time.
Others at the airport to welcome the President were Officials of the Nigerian Embassy in Iran, led by the Charge de Affaire, Dr Ali Magashi, the Minister of foreign Affairs, Mr Geoffrey Onyeama and the Minister of Power, Works and Housing, Mr Babatunde Fashola.
The Minister of State for Petroleum Resources, Dr. Ibe Kachikwu and the National Security Adviser, retired Major General Babagana Monguno, were also at the airport to welcome the President.
Buhari is expected to meet with his Iranian, counterpart, Hassan Rouhani, during his two-day visit to Tehran.
He will hold bilateral talks with other participating heads of state and government on the sidelines of the GECF.
President Buhari and the leaders of Iran, Russia, Qatar, the Netherlands, Venezuela, Oman, Algeria, the United Arab Emirates, Bolivia and other member-countries of the GECF are expected to review the current market outlook on gas and discuss strategies for boosting gas production during their meeting.
Nigeria and other GECF members currently account for 42 per cent of global gas production, 70 per cent of global gas reserves, 40 per cent of pipeline transmission of gas and 65 per cent of the global trade in Liquefied Natural Gas.
President Buhari will also meet with Nigerians resident in Iran.