Mayor de Blasio’s Halloween costume is giving New Yorkers “labor” pains.

The city’s first couple donned early 20th-century garb to dole treats to tykes at their annual Gracie Mansion Halloween party Saturday.

De Blasio dressed like a “labor activist,” an aide said. He wore an ill-fitting muddy-brown suit, a Bengal-striped blue-and-white shirt, a black newsboy cap, and a goofy tied scarf with a matching smirk. He held a hand-painted sign that read, “A Living Wage for a Hard Day’s Work.”

First Lady Chirlane McCrae played a “suffragette,” wearing a tasteful coral-colored floor-length dress, white gloves, and a sash that read, “Votes for Women.”

A stream of Batmen, skeletons, Disney princesses and animals marched up the porch to get goody bags and take photos with the mayor.

McCrae hugged a little girl dressed as Princess Jasmine as the mayor said, “Wow, I like your veil,” and posed for a picture with her.

To a little girl dressed in a pink princess dress, Hizzoner remarked, “Look at you! Beautiful,” before taking another snapshot.

As De Blasio and McCrae greeted families on the Gracie Mansion veranda, he said, “I’m proud of who we are.”

The first couple likes to match their outfits for the October holiday.

Last year they wore Mets uniforms last year during the team’s magical World Series bid, and they dressed like Greco-Roman deities in 2014.