A November 2009 AP file photo of Heidi Montag, left, and Spencer Pratt.
She cited irreconcilable differences in a court document submitted on Tuesday in Santa Monica, California.
Montag and Pratt are stars of the MTV series "The Hills" and have been married since last April. The series is in its final season.
Montag's two-page handwritten filing does not offer any more details on the couple's breakup. An e-mail sent to an MTV spokeswoman seeking comment was not immediately returned.
The filing also doesn't indicate whether Montag intends to file for divorce, which would formally end their marriage.
