In a video announcing the changes, Mattel executives cast the move as an act of progressivism, an acknowledgment that they believe it is simply the right thing to do.
"This is radical. Because we're saying there isn't this narrow standard of what a beautiful body looks like," Robert Best, senior director of product design, says in the video.
The video includes shots of a diverse group of girls playing with the dolls, echoing similar sentiments.
"It's important for Barbies to look different. You know, like the real people in the world," one little girl says.
Another girl, toting a Barbie in each hand, declares, "I like them, because this one looks like me and this one looks like my mom."
The new line of dolls will hit American stores this northern spring.
Barbie's Coke-bottle shape has long been held up as an emblem of persistent, unrealistic beauty standards for women.
By adding new body types, Mattel is aiming to change that conversation around one of its flagship brands.
"I don't know why Mattel waited this long, but I'm glad they're doing it," said Arun Jain, a marketing professor at the University of Buffalo. "And it should help them."
There isn't this narrow standard of what a beautiful body looks like.
Barbie's new body shapes are part of a broader effort by Mattel to recalibrate its toy assortment for a confluence of cultural changes, for a moment when America's non-white population is growing; when plus-size clothing brands are challenging traditional standards of beauty; and when mums and dads alike are deeply conscious of gender-based stereotypes.
For example, this northern spring, Mattel plans to roll out a new line of toys called DC Super Hero Girls. The collection of action figures, which portrays DC Comics characters such as Wonder Woman, is meant to offer girls an alternative to the uber-girly, dainty dolls that are typically marketed to them.
There is a clear dollars-and-cents incentive for Mattel to change its iconic doll: the company is desperately looking to regain momentum after it lost the licence to produce Disney Princess toys. Disney took that business to toymaking rival Hasbro, leaving Mattel without one of its key cash cows.
There have been other signs of unease at the company, too, including a chief executive shake-up about a year ago.
There have also been signs for some time the Barbie brand was not connecting with shoppers the way it once did. Barbie remains one of the best-selling dolls in the world, but sales have been soft recently.
By giving Barbie a variety of body types, Mattel is making a two-pronged gamble: it's hoping to appeal directly to little girls who might be more enticed by a doll that looks more like them, and it's hoping to convince parents to open their wallets by creating a feel-good, progressive halo around the dolls.
The company has also moved to make Barbie high-tech: it has begun selling Hello Barbie, a doll that uses voice-recognition software to have conversations with a child.