Mayor Michael Nutter visited Sunday with Lynette Gaymon, a geometry teacher at Charles Carroll High School, and Samantha Pawlucy, 16, The Philadelphia Inquirer reported.
Gaymon was accused of humiliating Pawlucy in class over a pink T-shirt she wore showing support for Republican presidential nominee Mitt Romney and his running mate, Paul Ryan, Sept. 28 for a school "dress-down" day.
Gaymon told the teenager that wearing a Romney/Ryan shirt in a "Democratic" school was as ridiculous as it would be for the teacher, a black woman, to wear a "KKK" shirt, the student said.
The teacher has apologized to the Pawlucy family, both sides have said.
Details of the mayor's visits were not reported.
Gaymon has received harassing phone calls, with one caller making a death threat, her family said, and the student said she has faced harassment from some classmates.
"It's up to my daughter," the girl's father said Sunday when asked what comes next. "We don't know what we want to do."