Former state Senator Mike Mazzei won the Republican gubernatorial primary runoff on Tuesday, defeating Oklahoma Attorney General Gentner Drummond.
The primary followed a June 16 first‑round result in which Drummond led by 0.3 percentage points, prompting a runoff.
Trump endorsed Mazzei in May, before the open primary, but the race remained competitive.
Mazzei loaned $11.6 million of his own money, while Drummond loaned himself $3 million, according to campaign finance records.
The conservative group Club For Growth spent about $8 million on television ads supporting Mazzei and attacking Drummond, per AdImpact tracking.
Prior to the runoff, Mazzei received endorsements from Governor Kevin Stitt and former Representative Markwayne Mullin.
Mazzei served in the state Senate for 12 years and was budget secretary in Stitt’s administration in 2019.
He is the favored candidate in the November general election against Democratic state Representative Cyndi Munson in a state that Trump won by 34 points in 2024.
His victory secures the Republican nomination for governor.

