Jason Everett Mumpower (born September 22, 1973) currently serves as Tennessee's 35th Comptroller of the Treasury. He was first elected to the position by the Tennessee General Assembly on January 13, 2021. He is responsible for leading the Office of the Comptroller of the Treasury, which comprises 12 divisions and more than 560 employees, and ensuring the Office fulfills its mission to make government work better.

Mumpower first joined the Comptroller's Office in December 2010, serving as former Comptroller Justin P. Wilson's Deputy Comptroller and Chief of Staff.

Mumpower was a member of the Tennessee House of Representatives representing the 3rd District, which consists of all of Johnson County and part of Sullivan County.

Mumpower was first elected to the Tennessee House in the 100th Tennessee General Assembly at the age of 23, and he served as the Republican Majority Leader, a position to which he was elected on December 13, 2006. He was a member of the Health and Human Resources Committee, the Government Operations Committee, and Finance, Ways and Means. He was previously Republican Caucus Assistant Leader.

With the Republicans holding a slim 50–49 advantage over Democrats within the Tennessee House of Representatives following the 2008 state elections, it was anticipated within the TNGA Republican House Caucus that Mumpower would be the elected in 2009 as next Speaker of the House, succeeding Democrat Jimmy Naifeh, who has held the position since 1991. However, Mumpower lost the House Speaker election to fellow Republican Kent Williams of Carter County. Williams was able to secure the vote of every House Democrat, plus his own, to become the first Republican Speaker of the House since 1969.

After serving 14 years in the General Assembly, Mumpower announced he would not seek reelection in 2010.

Mumpower co-sponsored the 2009 H.B. 1725 legislation sponsored by his fellow Bristol and Sullivan County member in the Tennessee House of Representatives, Rep. Jon Lundberg (the Tennessee Senate companion bill, S.B 1950 was sponsored by his fellow Sullivan County resident, Lt. Governor Ron Ramsey). H.B. 1725 – subject to approval by the Bristol Board of Aldermen – removes the right of all Bristol voters to participate within ballot questions for recall, initiative, and referendum provisions authorized by the city charter, and was enacted into law by the Tennessee General Assembly and assigned Private Chapter Number 18 by the Tennessee Secretary of State.

Mumpower voted for a measure to lift a cap preventing the construction of toll bridges and toll road projects across Tennessee during the 2008 session. The toll road legislation failed to be enacted by the Tennessee Senate.