The fashion designer has registered "Harper Beckham" with intellectual property authorities in Britain and Europe.
It'll allow her to bring out branded products including toys and clothing, and also protects Harper's name in the entertainment industry.
The names of Victoria and David Beckham's three other children have also been registered.
The application, filed on 22 December, says Victoria is the holder of the rights as parent and guardian.
It will mean the former Spice Girl is the only person who can legally use 'Harper Beckham' on products, also ranging from rag dolls to anti-wrinkle cream.
And it will prevent anyone else in the music, film or TV industries calling themselves by the name.
Harper is named after Harper Lee, the author of Victoria's favourite book, To Kill A Mockingbird.
The Beckham's family business is thought by experts to be worth hundreds of millions of pounds.
As well as Victoria's successful fashion line, they have endorsed products including perfume and underwear.
David Beckham registered his name in 2000 and Victoria did the same in 2002.
Cruz, Romeo and Brooklyn were all registered as trademarks at the same time as Harper.
Brooklyn, 18, has recently been making his own name as a photographer, with his first book due out in May.
Fourteen-year-old Romeo has modelled for Burberry, while 12-year-old Cruz is pursuing a music career.
George Sevier is from law firm Gowling WLG.
He's says it's a good move by Victoria Beckham.
"It is much easier to get a trademark registration when the application is made before the personality becomes famous.
"And having a trademark registration it makes it much easier to stop other people from using the name without permission.
"Victoria Beckham has applied for registration of Harper Beckham as a trademark across the EU. That's a sensible move."