Mr Stitt, 48, announced the positive test results on Wednesday after seeking a test due to feeling “a little achy” on Tuesday.
“I feel fine, I felt a little bit achy yesterday, didn’t have a fever but just a little bit achy so just did my regular testing and it came back positive,” he said on a conference call with reporters.
“I’ll be taking precautions, I’m now isolating away from my family. I’ll be working from home until it’s safe for me to get back to normal.”
His positive test results come as Oklahoma suffered a record-high number of new cases, with 1,075 bringing the state total to more than 22,000.
Oklahoma also recorded four additional deaths, bringing its statewide death toll to 432.
Oklahoma has resisted a statewide mandate on masks and has one of the country’s most aggressive reopening plans, while Mr Stitt himself often goes without a mask.
“We respect people’s rights ... to not wear a mask. You just open up a big can of worms,” he said, according to the Associated Press.
“A lot of businesses are requiring it, and that’s fine. I’m just hesitant to mandate something that I think is problematic to enforce.”
The governor said he is working with contact tracers to determine if he may have come in contact with anyone long enough to pass on the virus.
His wife and children tested negative.