Attending the annual rallies, Armenians began a march from the church of the Armenian Diocese of Tehran and gathered in front of the Turkish embassy.
A ceremony was held at the Armenian church of Tehran on April 23 and 24 to pay tribute to those killed a hundred years ago.
While a number of countries define the massacres as genocide and while Turkey accepts that many Armenians died in partisan fighting, the Turkish government denies that up to 1.5 million were killed and that it was an act of genocide.
Ankara believes that up to 500,000 Armenian were killed, but mostly due to war and starvation.
Last year, Turkish Prime Minister Tayyip Erdogan made unprecedented condolences to the grandchildren of Armenians killed at the time, but the legacy remains an obstacle to reviving frozen relations between Ankara and Yerevan.