The Melvin and Bren Simon Foundation is a private grantmaking organization founded by American billionaire real estate developer Melvin Simon, cofounder of Simon Property Group, and his second wife Bren Simon. The foundation supports a variety of left-of-center organizations severally associated with the Democratic Party, Clinton family, environmentalist advocacy, and civic causes in Indiana.
The Melvin and Bren Simon Foundation was founded as a private grantmaking philanthropic organization in July 1998 in Carbondale, Colorado, by billionaire Melvin Simon, co-founder of the Simon Property Group, and his second wife, Bren Simon, president of MBS Associates Inc., LLC, a property management company.  Following her husband’s death in September 2009, Bren Simon became the foundation’s sole trustee.  The foundation controls two websites, brensimonfoundation.com and brensimon.com, created in 2020 and 2021 respectively. 
On June 30, 2017, the foundation published an announcement detailing its financial support for 18 organizations, notably including the National Democratic Institute and Clinton Foundation, as well as environmentalist and animal welfare groups such as Friends of the Earth, the International Fund for Animal Welfare, and the Performing Animal Welfare Society. 
In September 2013, the foundation made a donation to the University of California, Los Angeles to fund the establishment of the Melvin and Bren Simon Digestive Diseases Center, which focuses on gastroenterological home health programs, minimally invasive procedures, and research. 
Other organizations that the Foundation supports include the Human Rights Foundation, Habitat for Humanity, Friends of the Earth, the Democratic Senatorial Campaign Committee, Clinton Global Initiative, the University of Arkansas’s Clinton School of Public Service, the Climate Reality Project, and the Aspen Institute. 
Melvin Simon was the cofounder (along with his brother, Herb Simon) of the Simon Property Group, an international property development and investment trust notable for developing hundreds of suburban shopping malls in North America, Europe, and Asia. Additionally, Simon was a co-owner of the Indiana Pacers, and during the 1970s and 1980s, a producer of adolescent-oriented films. Simon died in September 2009, leaving his widow Bren Simon as the Foundation’s sole trustee. 
Bren Simon, Melvin Simon’s second wife and widow, is the president of MBS Associates, Inc., LLC, a property management firm based in Indiana. From 1995 to 1998, Simon was president of Gambit Capital Management, an investment firm. Simon is the co-founder of the Family Support Center, a nonprofit child-abuse care center, as well as a board member of the Coalition for Homeless Intervention and Prevention and the Indiana Natural Resources Foundation.  In the run-up to the 2004 Indiana Gubernatorial election, Democratic politician and former chairman of the Democratic National Committee Joe Andrew announced that he was running for governor with Simon on his ticket as candidate for Lieutenant Governor. However, when Joe Kernan, then serving as Lieutenant governor, later announced his intention to enter the race, Andrew decided to drop out.