Gov. Andrew Cuomo sure has a lot to say when it comes to President Trump or Mayor Bill de Blasio — but when it comes to debating his GOP opponent for governor, he’s suddenly tongue-tied.

With three weeks to go until the general election, Cuomo has so far refused to go one-on-one with Republican challenger Marc Molinaro, which has led to growing criticism from good-government groups — and even fellow Democrats.

Cuomo isn’t even trying to stack the deck as he did in 2010 and 2014, when he agreed to debate only if the stage were filled with third-party gadflies to make sure the attacks wouldn’t be ­entirely focused on him.

This time, he’s just flat-out declining to even talk about having a debate.

When asked about his reluctance, Cuomo spokeswoman Dani Lever referred a reporter to the governor’s past remarks, such as when he said, “Yeah, that’s something we have to talk about,” when questioned on Sept. 25 about ­debating.

“Thank you very much, good to see you,” he added.

Cuomo’s refusal thus far to debate Molinaro face to face before TV cameras was even criticized by disgraced former Democratic Gov. Eliot Spitzer, who held two debates with GOP rival John Faso in 2006.

“Of course it is the best — and indeed a necessary — way to lift democracy above the platitudes of messaging paid for by the corrupt dollars that flow into the campaign war chests of incumbents,” said Spitzer.

Blair Horner, executive director of the New York Public Interest Research Group, a government watchdog organization, said: “The governor and his major opponents should duke it out in the public arena.”

Former Sen. Al D’Amato, a ­Cuomo-friendly Republican, also rapped the governor’s refusal.

“Politics aside, as a resident you want to see both candidates debate and compare them,” he said.

Cuomo has always played games with debates.

In 2014, he refused to debate Dem primary challenger Zephyr Teachout and agreed to face his Republican general election rival, Westchester County Executive Rob Astorino, only if all minor-party candidates participated.

Cuomo pulled the same stunt in 2010, insisting that his debate with GOP nominee Carl Paladino also include Jimmy McMillan of the “Rent Is Too Damn High Party” and Kristin Davis, the so-called “Manhattan Madam,” who mounted a quixotic bid that year.

Cuomo wouldn’t be the first frontrunner to duck a debate.

In 1994, George Pataki had no luck in trying to get a showdown with three-term Gov. Mario Cuomo, Andrew’s father.

Pataki ended up winning the election in a 49-45 percent upset.

The current governor this summer did debate primary challenger Cynthia Nixon, whose campaign alleged that he agreed only after being allowed to dictate the ground rules.

“People learn a lot from debates and candidates have an affirmative obligation to educate the public,” said David Birdsell, dean of public and international affairs at CUNY’s Baruch College. “There’s a matter of self-interest as well, developing a mandate based upon high levels of information of the people putting you into the office.”

Molinaro has accepted invitations to at least two debates in a bid to force Cuomo’s hand.

“Andrew Cuomo is a political coward; he rails away at carefully orchestrated media appearances, but cowers when it comes to debating his record against an actual challenger,” said Molinaro spokesman Bill O’Reilly.

The Republican agreed to an Oct. 24 debate on NY1 — provided Cuomo actually shows up.

A Molinaro spokeswoman said the campaign has also accepted an invitation from the League of Women Voters.

“Debates were good enough for Abraham Lincoln and they should be good enough for Gov. Cuomo,” said John Kaehny, executive director of Reinvent Albany.

But Cuomo’s commanding advantages in fundraising and in the polls mean there’s little chance he’ll agree to a prime-time debate, Birdsell said.