The theme park doesn't have weight restrictions, so Morales said she didn't know she couldn't go on the ride until she was about to board it.
Morales said she bought annual passes to the park last year and couldn't wait to check out The Wizarding World of Harry Potter.
"(I) couldn't fit on any of the Harry Potter rides because of my weight," she said. "(I) did a lot of bag-holding in Diagon Alley and that kind of thing."
She had hoped to ride the King Kong attraction, because its seat is a bench without a safety bar, but when she got to the front of the line, she told her daughters that she didn't think they'd fit without making others uncomfortable, Morales said.
A man waiting in line overheard their conversation and offered to wait for the next available ride so Morales could ride with her daughters.
During another trip to the park, Morales said she tried to spare herself from further embarrassment by asking workers if one fewer person could ride in her row.
She said they wouldn't allow it, because they said they have to "push for capacity."
"It's somewhat humiliating to have to ask for an accommodation because of one's weight -- that you have to put yourself out there and kind of beg to be able to ride and embarrass yourself because of weight," Morales said.
She filed a discrimination complaint with the Florida Commission on Human Relations. She said overweight people should be a protected class.
"Their interest is getting bodies and getting money and not accommodating paying customers," she said. "That's how I felt."
Morales said she was offered a $100 gift card, dinner and movie tickets, but she doesn't plan to return to the park.
WFTV asked Universal if it trains its workers to handle such incidents and if it considers Morales' request unreasonable.
"While we don’t comment on specific guest situations, we always strive to treat our guests with respect and we work to accommodate special requests when we can," a company spokesman said.