Thomas Allen Coburn (March 14, 1948 – March 28, 2020) was an American politician and physician who served as a United States senator from Oklahoma from 2005 to 2015. A Republican, Coburn previously served as a United States representative from 1995 to 2001.

Coburn was an obstetrician who operated a private medical practice in Muskogee, Oklahoma. He was elected to the United States House of Representatives in 1994 as part of the Republican Revolution. After being re-elected twice, Coburn upheld his campaign pledge to serve no more than three consecutive terms and did not seek re-election in 2000. In 2004, he returned to political life with a successful run for the United States Senate. Coburn was re-elected to a second Senate term in 2010 and kept his pledge not to seek a third term in 2016. In January 2014, Coburn announced that he would resign before the expiration of his final term due to a recurrence of prostate cancer. He submitted a letter of resignation to Oklahoma Governor Mary Fallin, effective at the end of the 113th Congress.

Coburn was a fiscal and social conservative known for his opposition to deficit spending, pork barrel projects, and abortion. Described as "the godfather of the modern conservative austerity movement", he supported term limits, gun rights and the death penalty, and opposed same-sex marriage and embryonic stem cell research. Many Democrats referred to him as "Dr. No" due to his frequent use of technicalities to block federal spending bills.

After leaving Congress, Coburn worked with the Manhattan Institute for Policy Research on its efforts to reform the Food and Drug Administration, becoming a senior fellow of the institute in December 2016. Coburn also served as a senior advisor to Citizens for Self-Governance, where he was active in calling for a convention to propose amendments to the United States Constitution.

Coburn was born in Casper, Wyoming, the son of Anita Joy (née Allen) and Orin Wesley Coburn. Coburn's father was an optician and founder of Coburn Optical Industries, and a named donor to O. W. Coburn School of Law at Oral Roberts University.

Coburn graduated with a Bachelor of Science in accounting from Oklahoma State University, where he was also a member of Sigma Nu fraternity. In 1968, he married Carolyn Denton, the 1967 Miss Oklahoma; their three daughters are Callie, Katie and Sarah, a leading operatic soprano. One of the top ten seniors in the School of Business, Coburn served as president of the College of Business Student Council.

From 1970 to 1978, Coburn served as a manufacturing manager at the Ophthalmic Division of Coburn Optical Industries in Colonial Heights, Virginia. While Coburn was manager, the Virginia division of Coburn Optical grew from 13 employees to over 350 and captured 35 percent of the U.S. market.

After recovering from an occurrence of malignant melanoma, Coburn pursued a medical degree and graduated from the University of Oklahoma Medical School with honors in 1983. He then opened Maternal & Family Practice in Muskogee, Oklahoma, and served as a deacon in a Southern Baptist Church. During his career in obstetrics, he treated over 15,000 patients, delivered 4,000 babies and was subject to one malpractice lawsuit, which was dismissed without finding Coburn at fault. Together Coburn and his wife were members of First Baptist Church of Muskogee.