Mark Ronson's Wife Files for Legal Separation

Mark Ronson and his wife of more than 5 and a half years are splitting up ... TMZ has learned.

The DJ and producer's wife -- Josephine de La Baume -- filed docs Thursday for a legal separation ... citing irreconcilable differences. She lists the date of separation as April 21.

The couple wed in September 2011. They don't have any kids together, and Josephine, a French actress, is asking for spousal support.

Ronson had a career year in 2016, winning Grammys for Record of the Year and Best Pop Group Performance with Bruno Mars for "Uptown Funk."