Bay Collective, which owns NWSL side Bay FC in America, will take control of the team under the agreement, with Sunderland AFC retaining a minority share.
The takeover, which is subject to approval from football authorities, will make Sunderland the second team in the network.
Kay Cossington, a former Football Association director who leads Bay Collective, said the group wants to create a platform for sustained success at the highest levels of the women’s game.
Cossington, the group's chief executive, said: "We couldn’t be more excited to partner with Sunderland AFC and to write the next chapter for Sunderland Women, a Club with such a proud history and strong identity.
"We are committed to honouring Sunderland Women’s DNA and legacy, protecting what makes this Club and community so special, and supporting the players, staff, and the Academy with cutting-edge resources, infrastructure, and training models tailored to the unique needs of women athletes."
The acquisition aims to upgrade the club's performance environments and matchday operations, with the side currently sitting eighth in WSL2.
It will also trigger wider investment in the Academy of Light training base, which supports the men's, women's and youth teams.
Sunderland's academy has a long history of producing top England internationals, with Beth Mead, Jill Scott, Steph Houghton and Lucy Bronze among its graduates.
Jill Scott in her role with Sunderland AFC’s official charity, the Foundation of Light. (Image: NQ)
Tom Burwell, chief executive of Bia Sports Group, said the agreement followed a comprehensive one-year process to find the right partner.
He said: "This agreement reflects a shared ambition to see our women’s team thrive at the highest level.
"Bay Collective brings world-class experience and resources, and this partnership creates an exciting platform for sustainable success, while keeping Sunderland’s identity and values at its core."
Sunderland AFC will continue to help operate the women's team alongside the new majority owners as they complete the current season.
Bay Collective was launched in 2025 with backing from Sixth Street's global platform to build a dedicated network of women's football clubs.
The WSL has also seen a multi-club-style takeover elsewhere, with London City Lionesses bought in 2023 by American Michele Kang, who also owns San Diego Spirit in the NWSL and Lyon.