Us Weekly magazine reported Ashley will return to New York University for her sophmore year while Mary-Kate will attend art school in California.
But Olsen spokesman Michael Pagnotta said Mary-Kate is not leaving NYU.
In a statement sent to E! News Tuesday, he said the 19-year-old will be doing "approved independent study" and "will continue to be enrolled" at NYU.
The billionaire twins got separate New York apartments in January and put their $7.3 million condo up for sale without ever living in it, E! said.
Us Weekly reported Mary-Kate wanted to study in California to be closer to her latest boyfriend, film student and Greek shipping heir Stavros Niarchos.
She also focused on arts studies at NYU last semester and interned for photographer Annie Leibovitz.