South Korea's Supreme Court has rejected a 30 million won ($A33,000) damage claim by an American composer who accused a South Korean kids content company of plagiarising his version of Baby Shark.
The decision on Thursday ends a six-year legal battle over the globally popular tune known for its catchy "doo doo doo doo doo doo" hook.
The top court upheld lower-court rulings dating to 2021 and 2023 that found no sufficient grounds to conclude Pinkfong infringed on Jonathan Wright's copyright.
Wright, also known as Johnny Only, had recorded his version in 2011, four years before Pinkfong's, but both were based on a traditional melody popular for years at children's summer camps in the United States.
The courts ruled that Wright's version did not differ enough from the original melody to qualify as an original creative work eligible for copyright protection, and that Pinkfong's song had clear differences from Wright's.
The Supreme Court said its ruling reaffirms the established legal principle on existing folk tunes as derivative work.
"The Supreme Court accepts the lower court's finding that the plaintiff's song did not involve substantial modifications to the folk tune related to the case to the extent that it could be regarded, by common social standards, as a separate work," it said in a statement.
Pinkfong said the ruling confirmed its version of Baby Shark was based on a "traditional singalong chant" that was in the public domain.
The company said in a statement to The Associated Press that it gave the tune a fresh twist by adding "an upbeat rhythm and catchy melody, turning it into the pop culture icon it is today".
Wright's South Korean lawyer did not immediately respond to requests for comment.
Pinkfong's Baby Shark became a global phenomenon after it was released on YouTube in 2015, with the original Baby Shark Dance video exceeding 16 billion views and peaking at No.32 on the Billboard Hot 100.
Baby Shark remains a crucial product for Pinkfong, which earned 45.1 billion won in revenue in the first half of 2025, according to its regulatory filing.
The company has turned the five-member shark family - Baby Shark, Mama Shark, Papa Shark, Grandma Shark, and Grandpa Shark - into TV and Netflix shows, movies, smartphone apps and world-touring musicals.