Margie Winters and her wife sat down with Action News on Thursday.
After eight years at Waldron Mercy Academy in Merion Station, Winters was fired at the end of June.
She says a parent found out about her marriage and complained to school officials.
The principal, who knew that Winters was gay, gave her a choice to resign or be fired.
"In my mind, for me to resign means that what this woman and what she believes the church is saying is true and I don't believe that's true," said Winters.
Winters was the school's religious education director.
The school's principal released a letter this week alluding to Winters' marriage to a woman as a conflict.
The letter said in part, "Our school recognizes the authority of the Archbishop of Philadelphia, especially in the teacher of religion to...to continue as a Catholic school, Waldron Mercy must comply with those teachings."
But on Wednesday, the Archdiocese of Philadelphia said Waldron is a private Catholic school and personnel decisions are made without the oversight of the Archdiocese.
More than 100 people, including parents, alumni and some students, met at Jack's Firehouse in Fairmount on Wednesday night to rally behind Winters.
Organizers of that event say they will continue to fight to help Winters get her job back.