Mackenzie Moretter, who suffers from a rare genetic disorder, invited her classmates to her 10th birthday party. None of them RSVP'd yes.
Mackenzie has Sotos syndrome, which has made it difficult for her to make friends.
"Her skull wasn't able to form completely," her mother, Jenny Moretter, told WCCO-TV. "Therefore it caused some brain damage."
Mackenzie's father, Matt Moretter, said her previous birthday celebrations "have, for the most part, been family."
"She wanted to have a big-girl party with friends coming over and stuff," he said.
Invitations were sent to students at Mackenzie's school. Her parents said her classmates don't know her very well, and none of them responded.
"I want so much for Mackenzie to belong," her mother said. "I want her to have friends and people to accept her for who she is."
So Jenny Moretter posted an open invitation on Facebook, asking girls around her daughter's age to show up.
"I honestly thought it would be a matter of a few other moms out there that I touched their heartstrings," she said.
The Facebook post was shared by hundreds of people, WCCO reported.
On the day of the party, about 400 newfound friends — including firefighters, Snoopy and a Minnesota Vikings player — showed up.
“It means a lot to me for all of you coming to spend time with me,” Mackenzie said.