According to Los Angeles County records, the Internal Revenue Service filed a lien on Tuesday against the starlet for the unpaid taxes from 2009.
Lohan is also facing a lawsuit brought by a paparazzo who claims the actress was in a car that struck him in Hollywood last year.
When asked about the lien, publicist Steve Honig said Lohan's finances are nobody's business but her own. He added that he had not seen the lawsuit from photographer Grigor Balyan.
Lohan remains on probation for a 2007 drunken driving case and a misdemeanor grand theft case filed after she took a $2,500 necklace without permission in January. She has been serving morgue duty to comply with her probation.
The Associated Press contributed to this report.