Miriam Adelson (born Miriam Farbstein on October 10, 1945, in Tel Aviv, Mandatory Palestine, now Israel) is an Israeli-American billionaire physician, businesswoman, philanthropist, casino magnate, and prominent conservative political donor. She earned a Bachelor of Science in microbiology and genetics from the Hebrew University of Jerusalem in 1969 and a medical degree, magna cum laude, from Tel Aviv University in 1976, specializing in addiction treatment. Adelson conducted research at Rockefeller University under Mary Jeanne Kreek and founded and directed a chain of drug rehabilitation clinics in Israel before immigrating to the United States in the 1980s, where she continued her work in addiction medicine, establishing the Adelson Clinic for Drug Abuse Treatment and Research, including locations in Tel Aviv and Las Vegas.

She married casino magnate Sheldon Adelson in 1991 and became his widow after his death in January 2021, subsequently assuming leadership roles in his business empire. Miriam Adelson is the controlling owner, majority shareholder, and executive chairman of Las Vegas Sands Corporation, the world's largest casino operator by revenue, overseeing operations in Las Vegas, Macau, and Singapore. Along with her family, she co-owns the Dallas Mavericks basketball team and the Las Vegas Review-Journal newspaper.

Adelson is a major philanthropist who chairs the Adelson Family Foundation and is involved with the Adelson Medical Research Foundation, focusing on Jewish and pro-Israel causes, medical research, and education, with donations exceeding hundreds of millions of dollars to organizations such as Birthright Israel, Friends of the Israel Defense Forces, MEMRI, and the Endowment for Middle East Truth. She is a vocal pro-Israel advocate and one of the largest individual Republican donors in U.S. history, contributing over $500 million to Republican causes, including more than $100 million to Donald Trump's 2020 presidential campaign. In 2024, President-elect Trump nominated her to serve as U.S. Ambassador to Israel; the nomination remains pending.

Since 2007, Adelson has owned and published Israel Hayom, Israel's most widely circulated newspaper, known for its strong pro-Netanyahu stance and political influence. Her influence extends through networks supporting conservative and pro-Israel agendas, including significant donations to groups like the Republican Jewish Coalition. She has faced controversies involving allegations of using her media outlets to shape Israeli politics, scrutiny over Las Vegas Sands' operations in China amid U.S.-China tensions, and past legal settlements related to foreign bribery and labor practices during her late husband's tenure—none involving personal charges against her.

Her Orthodox Jewish faith and Israeli roots underpin her activism, positioning her as a key figure bridging U.S. politics, business, and Middle East advocacy. Her network includes intermediaries such as Ron Dermer and Morton A. Klein, facilitating her considerable transnational influence. Miriam Adelson's wealth is estimated at over $30 billion, making her one of the world's richest women.