According to the court documents, Simpson has cited "irreconcilable differences" as the legal reason for the split. The 24-year-old is seeking spousal support, reports TMZ.
"After careful consideration, we have made the difficult decision to file for divorce," the couple said in a statement.
They added: "We remain friends and deeply committed and loving parents to our son Bronx, whose happiness and well-being remains our number one priority. We ask that everyone honour our privacy as we navigate this next phase of our lives."
Simpson is seeking primary physical custody of 2-year-old Bronx with visitation for Wentz. She also hopes to drop the moniker Wentz from her name.
The pair married in May 2008. Their official date of separation is to be determined, according to the court papers.