Maria Vittoria Longhitano, 35, will be ordained in an Anglican church in Rome, a stone's throw from the Vatican, this month.
She is not an Anglican, but a member of a small Catholic order called the Old Catholics, who broke away from the main body of the Church in the 19th century.
They do not believe in papal infallibility or the Immaculate Conception and are not recognised by the Vatican.
Mrs Longhitano, a married teacher from Milan, said she hoped to stimulate a debate and break down the "prejudice" within the Catholic Church when she is ordained at All Saints Anglican Church, near Rome's famous Spanish Steps, on May 22.
"My ordination represents a great chance for all women of faith. It means hope, it means giving a push to an important debate between Catholics on the issue of denying women the possibility of fulfilling their vocations and being ordained as ministers," she said.
A spokeswoman for All Saints said that Miss Longhitano, who has been a deacon within the Old Catholics since last year, was not being ordained into the Anglican Church itself.