The Oklahoma lawmaker acknowledged that Rubio “hasn’t moved as much as he should have” in national polls, but was otherwise complimentary.
Rubio currently trails businessman Donald Trump and Sen. Ted Cruz (R-Texas) in national polls.
He picked up the endorsement of influential conservative Rep. Trey Gowdy (R-S.C.) this week.
Inhofe also expressed admiration for another Republican presidential candidate, Ohio Gov. John Kasich.
“I was in a Bible study with him for eight years and know him intimately,” he said.
Inhofe said he was puzzled by the governor’s low polling.
“For some reason, there’s something about him that just hasn’t sold. If you look at all the governors and former governors in the field, he’s done far more than any of the others,” he said. “And besides, he’s from Ohio.”