The Catholic educational institution dismissed English/religion teacher Kristen Ostendorf on Aug. 22, the Twin Cities web site said. Ostendorf said the school gave her no reason for her termination.
But Ostendorf's dismissal came after one day after she disclosed her sexual orientation, saying she was in a committed relationship with a woman, MinnPost reported.
Ostendorf's firing is the second instance of controversy over a staff member's sexual identity.
Earlier this summer, Bill Hudson resigned from Grace High School as its president after disclosing to the board that he has been in a long-term, committed same-sex relationship. That lifestyle clashes with the Catholic Church's official religious doctrine.
Hudson is now taking a new job as an administrator and fundraiser at Mounds Park Academy in Maplewood, according to a Pioneer Press news report.