Not that the Kardashian girls' workday is anything like most of ours ... but they clothing designers are giving women advice on how to dress for work.

Kim, Khloe and Kourtney posed as sexy secretaries and Kim uploaded the shots to Instagram, captioning the photos, "business women swag."

The 31-year-old showed off her famous curves in a pencil skirt, button-down blouse, suspenders and a bow tie, while Kourtney showed off her legs in tailored shorts, a blazer and tie. Meanwhile, Khloe wore a circular flannel skirt with a thigh-high slit.

A second shot shows Kim "unbuttoned," which she captioned, "So sophisticated lol."

The last shot shows Ms. Kanye in an evening gown ... perhaps for after-dinner drinks with the boss???

Meanwhile ... Kim arrived back in LA Friday after a week-long vacay with her lovey Kanye in Hawaii. And what was the first thing she did after touching down? She got her nails did, of course!