The No Doubt singer cited irreconcilable differences in her petition, TMZ reported. Bush frontman Rossdale also filed divorce papers at the same time.
"While the two of us have come to the mutual decision that we will no longer be partners in marriage, we remain partners in parenthood and are committed to jointly raising our three sons in a happy and healthy environment," the couple said in a statement provided to E! News. "To that end, we respectfully request privacy from the media during this time."
Both Rossdale and Stefani are asking for joint custody of their three sons -- 9-year-old Kingston, 6-year-old Zuma and 1-year-old Apollo.
Sources told TMZ the couple do not have a pre-nuptial agreement, so according to California law, they'll likely split all assets 50/50. Stefani is reportedly worth $58 million, while Rossdale's estimated worth is $35 million.
In her divorce filing, Stefani sought to deny her husband spousal support.