Why? Because the annual fashion event is far too prestigious for a celeb like Koko.
Radar Online reports that Vogue Editor In Chief Anna Wintour blacklisted her and sister Kourtney for being too "C-list".
But Khloe hasn't let it get her down (we don't think??)
While her sisters and mother walked the carpet on Monday, she tweeted her adoration for them.
"Just fed the baby. Back to catching up on these LEEWWWWEKSSSS #MetGala," she wrote on Twitter.
Her first tweet was followed by: "I seriously can not get over how incredible my sisters look tonight!!!! I’m dreaming of them."
We guess the Kardashian name can't get you everywhere.