Lucie Myslikova, a film and animation student from the Czech city of Brno, was captured in her uniform confronting a shaven-headed demonstrator.
The rally was held on May Day by the neo-Nazi Workers Party of Social Justice.
The photo has since gone viral.
"I wasn't afraid," Lucie told the BBC by telephone from her school.
"I went to the counter-demonstration as someone who was determined to change things. To me it makes sense to try and change the world around me," she went on.