The Yorkshire Building Society has launched a three-year partnership with the charity End Youth Homelessness.
The society, which last year won Business of the Year at the Third Sector Business Charity Awards, said it hoped to raise £750,000 for the charity through the partnership.
EYH helps young people become more financially secure by providing rent deposit guarantees, grants for household essentials and practical advice.
The society said it hoped the funds raised would support 700 young people into their own rented homes.
The charity was chosen after a selection process that culminated in a vote involving society staff and members.
Nick Connolly, director of EYH, said: "As our biggest corporate sponsor to date, Yorkshire Building Society’s support will have a transformational effect on the young people we work with, enabling them to escape homelessness for good."