Second grade doesn’t get classier than this.

A dapper, downtown 7-year-old turned the opening day of school into a true Manhattan “opening” yesterday — spurning T-shirt and shorts for a sleek black tuxedo.

Kyle Falls said it was his own decision to spice up the first day of classes at the spiffy Spruce Street School — which opened at a new site in a luxury tower designed by famed architect Frank Gehry.

“It’s a very special thing, the Frank Gehry building. It looks really cool, and I figured I should dress up,” said Kyle, whose family had been keeping an eye on the construction of the high-end tower.

His dad, Tom, said the tuxedo was a remnant of Kyle’s sixth-birthday party — a secret agent-themed blowout in honor of his son’s idol, James Bond.

He said that he and his wife had put Kyle in a normal schoolkid getup for the first day of classes when a light bulb seemed to suddenly go off in the boy’s head.

“We had him dressed in a T-shirt and camo pants, and he’s like, ‘Wait a minute . . . I need my tuxedo,’ ” said Tom.

“And then we were scrambling trying to find it.”

Kyle’s duds didn’t elicit much of a reaction from other pupils at the school, which serves 290 kids in pre-K through second grade.

But the garb did catch the attention of Mayor Bloomberg, who told Kyle, “You look really fancy,” according to the proud dad.