In an annual report on the role of women in the future of the Church, Open Doors found that a number of evangelists, Sunday school teachers and house-church leaders were female.
Christianity is suppressed in Iran because conversion away from Islam is illegal. Despite this, there are an estimated 800,000 converts attending underground churches throughout the country.
Azada, a woman who runs a house church, told Open Doors Iranian women are attracted to Christianity because they gain a new found confidence in Jesus.
Women who become Christians, she said, find that they "are loved, they are wanted, and they can come to God just as they are, without any shame".
"Many women risk imprisonment and torture by being active evangelists," she continued. "And because God gives them the strength to take this risk, each day new people, men and women, get to know the love of Christ and get to know their true identity: beloved children of God."
Another convert, named as Shifa, has launched an online church group where Iranian converts can connect with other Christians and encourage each other in their faith.
Shifa, who no longer lives in Iran, to help others understand the Bible and answer their questions.
"What I didn't have then - pastoral care and someone to disciple me - I can give to them now," she told Open Doors, "The Bible alone is not enough. To grow as a Christian you also need your fellow Christians to grow and to pray with."
According to the World Watch List published last week by Open Doors, Iran is the eighth most dangerous country for Christians to live in.