The Australian actress will also produce the live-action movie, a joint project between Warner Bros and Barbie manufacturer Mattel.
“Over the brand’s almost 60 years, Barbie has empowered kids to imagine themselves in aspirational roles from a princess to president,” Robbie said in a statement.
“I’m so honoured to take on this role and produce a film that I believe will have a tremendously positive impact on children and audiences worldwide.”
The film will mark the first time the toy has been brought to the big screen.
Wolf Of Wall Street star Robbie, 28, will co-produce alongside her husband Tom Ackerley and Josey McNamara from her LuckyChap Entertainment production company.
Comic actress Amy Schumer was previously in line to play Barbie in the film, but pulled out of the role in 2017.
“Barbie is one of the most iconic franchises in the world and we are excited to partner with Warner Bros Pictures and Margot Robbie to bring her to life on the big screen,” Ynon Kreiz, chairman and chief executive of Mattel, said.
A release date for the film has not been set and no director has been named.