The snap shows Kloss in a wedding dress and Kushner, younger brother of Jared Kushner - Donald Trump's son-in-law and senior adviser - in a tuxedo.
Writing next to the image on Instagram and Twitter, the model simply marked the date: "10.18.2018 ❤️"
People magazine reports the couple married at a small ceremony in upstate New York and will have a larger celebration in the spring.
Kloss is a Vogue cover girl who has modelled for Victoria's Secret and numerous luxury brands, and has recently been confirmed as the new host of US fashion design show Project Runway.
She is also the founder of Kode With Klossy, which hosts coding summer camps for teenage girls.
Her publicists have not given any details about the big day.
