The "Sweet Home Alabama" star has teamed up with bosses at Otter Media, a joint venture founded by officials at The Chernin Group and AT&T, to form the company under the banner Hello Sunshine.
All content will be created for and by women on multiple platforms, and will start rolling out next year, reported Variety.
Witherspoon will also continue to produce projects under her Pacific Standard production company.
"I'm thrilled to be partnering with Peter Chernin and AT&T on this exciting new company," a statement from Witherspoon read.
"Hello Sunshine is deeply committed to creating content that will reach women where they spend time, whether it is at a movie theater, at home or on their mobile device. Women are looking for entertainment that speaks to them about what they value. Hello Sunshine will make content that entertains, educates and brings women together.