Featuring workers in costumes from the parks' "Indiana Jones" and "Star Wars" themed rides, among others, the rally was organized by unions representing some 14,000 Disneyland employees, from rollercoaster operators to candy makers.
Slogans among the signs being carried included "Mickey would want fair pay" and "Disney, don't be the villain" at the march in Anaheim, near Los Angeles.
"We deserve fair wages," said 44-year-old Disneyland employee Ginny Cristales.
"A strike is our last resort, that we're not wanting to do. But if Disney doesn't comply and give us what we need, then we're all ready."
Disney has been in negotiations since April with the four California unions representing its park employees.
The talks have so far yielded nothing, and unions accuse the so-called "Happiest Place in the World" of intimidating employees.
Disney is claimed to have reprimanded and issued warnings to more than 500 employees for wearing a union pin featuring an image of Mickey Mouse's glove clenched in the shape of a fist.
"Last week, I saw a manager telling one of the cast members to remove her badge. He told her that it will be on her record card," said Cristales.
"She was stressed and she got scared."
The allegations have prompted an investigation by the National Labor Relations Board.
Disney has said the union buttons violate its "Disney Look" dress code.
Employees will vote on whether to authorize a strike this Friday. If the action is approved, unions will then decide on its terms and duration.
Contract talks with Disney are set for next Monday and Tuesday.
'We make the magic'
In the wake of last year's devastating strikes by Hollywood actors and writers, another large-scale walkout at Disney would be historic.
Employees at the Disneyland resort -- composed of the Disneyland and Disney California Adventure theme parks -- have not gone on strike since 1984, according to the LA Times.
But Cristales, a mother of four, said her $2,800 monthly wage does not even cover her family's rent.
"We make the magic, they make the money," went one of the chants heard Wednesday, as passing cars honked in support.
"Disney will invest $2 billion in its park but refuses to pay workers a living age" read a slogan on a protesters' T-shirt.
Protesters marched to the park's perimeter, where they tried to set up for speeches, but were told by security to move to a car park some 200 yards (meters) away.
"With today's rally, we continue to be focused on the wellbeing of our guests and cast members," said Disney in a statement Wednesday.
"We remain committed to the upcoming meetings on July 22-23 and reaching an agreement with Master Services that focuses on what matters most to cast members, positions Disneyland Resort for growth and job creation and enables us to continue delivering incredible guest experiences."
