Gentner Drummond (R) and Mike Mazzei (R) advanced to the August 25 Republican primary runoff after defeating seven other candidates in the primary on June 16. Incumbent Gov. Kevin Stitt (R) is term-limited and retiring from public office. In the primary, Drummond received 25.9% of the vote to Mazzei’s 25.5%.

The Oklahoman's Alex Gladden wrote, "In Oklahoma, a highly conservative state, the Republican primary often determines who will be the next governor." In 2024, Donald Trump (R) received 66.2% of the vote, and it was Trump's fifth-best performance in any state that year. In 2022, Gov. Stitt was re-elected with 55% of the vote. The last Democrat elected governor was Brad Henry (D) in 2006.

In the runoff, Drummond has campaigned on his record as attorney general, and says he "pushed back on the separation of church and state, against Big Pharma, against State Farm, against out-of-state companies that would injure Oklahomans’ home, payroll, paycheck, future. I’m the guy fighting for you, that brings in a lot of out-of-state money." Mazzei has campaigned on receiving President Donald Trump's (R) endorsement and supporting a conservative vision for the state: "Now with the runoff election, there’s a clear difference between Mr. Drummond and me: I am the complete and total endorsement of President Donald Trump. I’m running for governor to move Oklahoma in a more conservative direction.”

Drummond was elected state attorney general in 2022. He is campaigning on reducing the cost of living, and his campaign website includes a pledge to "cut taxes responsibly without sacrificing schools, roads, or public safety." Drummond is also campaigning on working with the state's tribal communities to improve the economy. His campaign website says he wants to "[a]dvance strategic partnerships with Tribal Nations to create jobs and investment in our state." The Oklahoma Fraternal Order of Police endorsed Drummond's campaign.

Mazzei is a former Oklahoma Secretary of Budget and a former state senator. He is campaigning to eliminate the state's property tax, and said to afford the cut, he would "promote [a] pro growth economy with lower income taxes and less regulations." Mazzei is also campaigning to stop foreign ownership of public lands, and his campaign website says he wants to "prohibit foreign governments and foreign-controlled companies from owning Oklahoma land." Trump and U.S. Rep. Josh Brecheen (R-Okla.) endorsed Mazzei.

According to Oklahoma Voice's Nuria Martinez-Keel, candidates in the primary contributed $22 million of their own money to their campaigns. Martinez-Keel wrote, "Self-funding in the 2026 race already outpaces past election cycles. Republican Gov. Kevin Stitt, a self-made millionaire, put $4.9 million of his own funds into his 2018 gubernatorial campaign and nearly $2 million when running for reelection." Drummond has contributed $2.5 million to his campaign, and Mazzei has contributed $11 million. To read more about campaign finance, click here.