Kelly in 2013 founded the group Ordain Women, which has pushed for gender equality. A panel of three men held a church disciplinary hearing for her on Sunday in Virginia, where she lived until recently, and their verdict was delivered by email.
"Our determination is that you be excommunicated for conduct contrary to the laws and order of the Church," Kelly's former ecclesiastical leader in Virginia, Bishop Mark Harrison, said in the message.
"These conditions almost always last at least one year," it said, adding that if she showed "true repentance" and gave up teachings and actions that "undermine the Church, its leaders, and the doctrine of the priesthood," she could be readmitted.
Kelly, a former Washington human rights attorney, said the decision had forced her out of her community and her congregation and was exceptionally painful.
"Today is a tragic day for my family and me as we process the many ways this will impact us, both in this life and in the eternities," Kelly said in a statement.
