Disney has been told it may have to sell the rights to use Mickey Mouse in South Africa if it loses a court battle over the song The Lion Sleeps Tonight.
The Lion King film was made into a stage show
Relatives of the song's original composer, Solomon Linda, say they are entitled to $1.6m in royalties from the track, used in The Lion King.
If Disney loses the case, it may have to sell over 240 trademarks, including Mickey Mouse, to pay the family.
A Pretoria court ruled the trademarks would remain part of the case.
Mr Linda, a Zulu migrant worker, composed the song, called Mbube, in 1939 and it has since been recorded by at least 150 artists around the world.
It features in The Lion King's film and stage versions.
He sold the copyright to a local firm in 1939, but his lawyers say it should have reverted to his heirs 25 years after his death in 1962.
The song became one of the most popular in Africa. It was later discovered by the US folk singer Pete Seeger.
Disney may have to sell the Mickey Mouse trademark in South Africa
US songwriter George David Weiss rewrote the song as The Lion Sleeps Tonight. It was later covered by Dave Newman and Tight Fit, among others.
The song has reportedly earned more than $15m (£8.4m) because of its use in the Lion King movies, but Mr Linda's family received $15,000 (£8,400).
Adri Malan, spokeswoman for the family's lawyers, said of Tuesday's ruling: "This means that Mickey Mouse is still in captivity."
But Disney spokeswoman Joyce Lorigan said the ruling had no real impact on the substance of the issue.
"The real issue in this lawsuit is whether Linda's estate or Abilene Music Publishing - who bought the rights to the song from Linda's wife - owns the copyright to The Lion Sleeps Tonight," she said in a statement.