Gilbert, 47, who played Laura Ingalls, also known as "Half Pint," during the entire run of the show from 1974-83, married Boxleitner in 1995.
Although California is a no-fault state, she cited irreconcilable differences as her reason for wanting the divorce, the Monday filing stated, aceshowbiz.com reported Friday. It also stated Gilbert is seeking joint custody of their 15-year-old son, Michael, named after her mentor on "Little House," Michael Landon.
The couple also has three grown sons from previous marriages.
Gilbert is asking not to have to pay spousal support for Boxleitner, 61, whose credits include the 1983 television series, "Scarecrow and Mrs. King," "Babylon 5" and the two "Tron" movies, The Hollywood Reporter reported.
The divorce filing comes the same week Gilbert's sister Sara announced the break-up of her 10-year relationship from partner Allison Adler.