Diane Marie Hendricks is an American billionaire businesswoman, philanthropist, and prominent conservative political donor. Born in 1947 in Wisconsin, she co-founded ABC Supply Co. Inc. in 1982 with her late husband, Ken Hendricks, starting from a single roofing supply outlet in Beloit, Wisconsin. Under her leadership as chairman and co-CEO, ABC Supply has grown into the largest wholesale distributor of roofing and other exterior and interior building products in North America, with over 900 locations across the U.S. and Canada. Following Ken Hendricks' death in a construction accident in 2007, Diane assumed full control and expanded the company significantly, achieving a reported net worth exceeding $11 billion as of recent Forbes rankings. She is also involved in real estate development through her company, Hendricks Holding Company, which manages diverse investments including hotels, manufacturing, and entertainment ventures.

Hendricks is one of the most influential Republican donors in the United States, particularly in Wisconsin, where she is recognized as the state's largest political contributor. She has donated tens of millions to conservative causes, including support for Donald Trump's presidential campaigns, Wisconsin Governor Scott Walker, and organizations like Turning Point USA, with Charlie Kirk as a major recipient of her financial backing. Her political activities extend to advocacy for school choice, tax reforms, and conservative policies, often through her role on boards and as a member of the Republican National Committee. Additionally, Hendricks has produced films and supports cultural initiatives, blending her business acumen with philanthropy in education and community development in Wisconsin.

Throughout her career, Hendricks has been praised for her entrepreneurial success and contributions to job creation but has faced criticism for her political donations and influence in state politics, including allegations of benefiting from government contracts awarded to her companies. She resides in Beloit, Wisconsin, and continues to shape the state's business and political landscape.