Duplantis won the award in 2024 in recognition of his Olympic gold medal and world records, and took the title again this year following another four world records and his gold at the World Athletics Championships, where he cleared a height of 6.30m, his 14th world record in all.
The award was decided by public vote, and the 26-year-old beat fellow athlete Sydney McLaughlin-Levrone (USA), footballers Mohamed Salah (Egypt) and Mariona Caldentey (Spain), boxer Terence Crawford (USA) and baseball player Shohei Ohtani (Japan) to the trophy.
Mondo was not present at the awards ceremony in Salford, UK, but instead gave his acceptance speech via video.
"Hey everyone! This is Mondo here. I just want to say thank you so much BBC for giving me (World) Sport Star of the Year award. I am super honoured and super appreciative of this," he began, before giving a nod to the British public who voted for him.
"I wish I was there with you guys, having a pint to celebrate! Hopefully next year! Thank you guys again, see you next year."
Formerly the BBC Overseas Sports Personality of the Year and first awarded in 1960, Duplantis joins Roger Federer, Usain Bolt, Muhammad Ali and Greg Norman as its only multiple winners.
The main award on the night, The 2025 BBC Sports Personality of the Year, was won by golfer Rory McIlroy.