Jeffrey James DeWit is an American businessman and politician who served as the chair of the Arizona Republican Party from January 2023 to January 2024. A member of the Republican Party, DeWit became the State Treasurer of Arizona in 2015, succeeding Doug Ducey. DeWit said in 2016 that he did not plan to seek re-election in 2018. In 2017, President Trump nominated him to be chief financial officer of NASA. His nomination as chief financial officer of NASA was confirmed by the U.S. Senate in March 2018. He resigned from NASA in February 2020 and joined Trump's 2020 campaign later that year.

The Arizona State Treasurer is the state of Arizona’s chief banker and investment officer. The Treasurer’s Office accounts for and manages the cash flows of state government, directs the state’s banking services, disburses public funds, and manages Arizona’s investment portfolio. The state treasurer also serves on the management boards of a number of public entities. The state treasurer is one of six statewide elected officials and serves a term of four years. A person may only serve as state treasurer for two consecutive terms. The Treasurer is third in the line of succession to the office of Governor of Arizona.