A kindergarten teacher upstate taught her kids a valuable lesson this week when she showed up drunk to school — vodka-and-lemonade in hand — and got busted for DWI, cops said.

Kimberly V. Grover, 47, was arrested Tuesday morning by a Granville Police sergeant shortly after arriving at Mary J. Tanner School with the cocktail, according to officials.

The cop, who serves as the school resource officer, saw the boozed up instructor stumbling in the parking lot and allegedly smelled alcohol on her breath.

Authorities said he asked her to take a field sobriety exam and a breathalyzer test, both of which she failed.

Grover allegedly blew a 0.13 — nearly double the legal limit — and was taken into custody. She was later charged with driving while intoxicated for operating her vehicle on the school’s property.

Cops said she had a cup of vodka-and-lemonade when she showed up Tuesday morning.

After her arrest, Grover was released by police, pending prosecution in Granville Town Court.

Local school officials told The Post Star that she had been a teacher for 18 years, though her status is now unclear.

School Superintendent Thomas McGurl said Thursday that the district was taking Grover’s arrest “very seriously” — but they had no comment on whether she still had a job.

“So much for teaching by example,” joked one Facebook user.

“Teaching must be a very stressful job,” another person said. “Doesn’t ever excuse showing up to work drunk though.”