The former television journalist cited irreconcilable differences, but offered no additional details about the break up.
She didn't list the date of the separation, although it became public knowledge on May 9.
A week later, the former California governor and one-time action star admitted he fathered a child with their housekeeper Mildred Baena 13 years ago.
The filing, which Maria signed nearly two weeks ago, signals an end to a union that began with a fairytale wedding on a spring day in 1986 in Cape Cod.
The couple do not appear to have had a premarital agreement.
That means the actor's earnings from his Hollywood career, which allowed him to forgo a salary as governor and commute by private jet to Sacramento, will probably be evenly divided with his estranged wife.
Maria is seeking spousal support but any amount would be determined later, either through a settlement agreement or by a judge. The divorce is expected to be handled mostly behind closed doors.
Maria, a member of America's historical Kennedy family, has received a lot of support from A-list friends and from those she's met through her philanthropic work.
The housekeeper who had a child with Arnold speaks out