David Barton (born January 28, 1954) is an evangelical Christian political activist and author. He is the founder of WallBuilders, LLC, a Texas-based organization that promotes his views about the religious basis of the United States.

Barton has been described as a Christian nationalist; his work is devoted to advancing the idea that the United States was founded as an explicitly Christian nation and rejecting the consensus view that the United States Constitution calls for separation of church and state. Historians have described his research as "flawed" and containing "outright falsehoods".

Barton is a former vice chair of the Republican Party of Texas and served as director of Keep the Promise PAC, a political action committee that supported the unsuccessful Ted Cruz 2016 presidential campaign.

Barton is a lifelong resident of Aledo, Texas, a suburb of the Dallas-Fort Worth Metroplex. He graduated from Aledo High School in 1972. He received a Bachelor of Arts degree in religious education from Oral Roberts University in 1976.

After graduating from college, Barton served as a youth pastor at churches in Tulsa, Oklahoma. He was employed as a teacher of math and science and eventually became principal at Aledo Christian School, a ministry of the charismatic church started by Barton's parents.

In 1987, Barton formed Specialty Research Associates, Inc., a company which said it focused on historical research "relating to America's constitutional, moral, and religious heritage". Specialty Research Associates submitted amicus curiae briefs in court cases. In 1988, the company became WallBuilders.

Barton is the founder and president of WallBuilders. WallBuilders publishes and sells most of Barton's books and videos, some of which present Barton's position that the modern view of separation of church and state is not consistent with the views of the Founding Fathers. Barton has argued that the religion clauses of the First Amendment were intended only for monotheistic religions, and perhaps solely Christianity. A 2005 Time magazine article entitled "The 25 Most Influential Evangelicals" called Barton "a major voice in the debate over church–state separation" who, despite the fact that "many historians dismiss his thinking ... [is] a hero to millions—including some powerful politicians". Barton has appeared on television and radio programs, including those of Republican presidential candidate Mike Huckabee and Glenn Beck. Beck has praised Barton as "the Library of Congress in shoes". In September 2013, he returned to the political arena and advised state legislators on how to fight the Common Core academic standards promoted by the Obama administration.

Barton was the vice chairman of the Texas Republican Party from 1997 to 2006 under state chairman Susan Weddington. He has also acted as a political consultant to the Republican National Committee on outreach to evangelicals.^{[better source needed]} There was a Tea Party movement to get him to run against Senator John Cornyn in the 2014 Senate election from Texas. However, Barton announced on November 6, 2013, that he would not run for the seat. Barton headed the Keep the Promise PAC, a political action committee supporting Ted Cruz during his campaign for election as U.S. President in 2016. Cruz failed to receive the Republican nomination. Barton has also advised Newt Gingrich.