Thetus Willrette Sims (April 25, 1852 – December 17, 1939) was an American politician and a member of the United States House of Representatives for the 8th congressional district of Tennessee.

He attended a private school at Martin Mills and moved with his parents to Savannah, Tennessee, in Hardin County in 1862 during the Civil War.

[1] He married Nannie Kitrell on December 26, 1877, and they had seven children, Edna, Erskine, Tom, Elizabeth, Marie, Paul, and Enid.

[5] Returning to Lexington, Tennessee, in Henderson County, Sims resumed the practice of law for a few years.

He is interred at Rock Creek Cemetery in Washington, D.C.[6] He was the father-in-law of politician Louis Brownlow.