Dean M. Barkley (born August 31, 1950) served as a member of the United States Senate, representing Minnesota from November 4, 2002 to January 3, 2003. Barkley is a member of the Independence Party of Minnesota, formerly the Minnesota Reform Party.

Barkley was born in Annandale, Minnesota. He received his BA and JD from the University of Minnesota.

Barkley had been appointed director of the Office of Strategic and Long Range Planning (known as Minnesota Planning) by Governor Jesse Ventura in January 1999. An early activist in the Minnesota Reform Party, Barkley ran for the U.S. House in 1992 and the U.S. Senate in 1994 and 1996 and was chairman of Ventura's successful gubernatorial campaign. Prior to entering government, Barkley practiced law and ran several small businesses.

Ventura appointed Barkley to complete the Senate term of Paul Wellstone, who died in a plane crash on October 25. Barkley served until the 107th Congress ended on January 3, 2003, when he was replaced by Norm Coleman, who had been elected on November 5, 2002 to the term lasting from 2003 to 2009.

Barkley's appointment was somewhat controversial, as Ventura had previously stated that he would not appoint a replacement for Wellstone, preferring to wait for the election results. Ventura's subsequent reversal was explained by him as being due to his disgust at Wellstone's memorial service, which he felt was used as a political rally for the Democratic Party. This was compounded by the fact that the established political parties refused to take the third-party candidate for the position seriously, or to allow that person to participate in pre-election debates.

During his short tenure, Barkley passed legislation establishing a memorial for Wellstone and provided the pivotal vote in clearing the final passage of the Homeland Security Act. Barkley briefly considered resigning a few days early to give incoming Senator Coleman higher seniority but decided against it upon learning that the seniority would only affect office space and other perks but not committee assignments.