The Sesame Workshop says she is being introduced as part of a campaign to take the stigma away from the disorder.
They also hope Julia will help those who are dealing with autism.
The workshop says she’ll be portrayed as a girl who “does things a little differently” when playing with her Muppet friends, including Elmo and Abby.
“If you’re five years old, and see another kid not making eye contact with you, you may think that child doesn’t want to play with you. But that’s not the case,” Sherrie Westin told People Magazine.
“We want to create greater awareness and empathy.”
Julia won’t feature in the Sesame Street television show but she will be included in digital and printed storybooks.
“Families with autistic children tend to gravitate toward digital content, which is why we created Julia digitally,” said Ms Westin.
“We want parents and children to understand that autism isn’t an uncomfortable topic.”
Sesame Street is also producing online tools as part of its See Amazing in All Children initiative, to help people affected by autism manage everyday activities.
Their guides, aimed at families with children aged between two and five, include ones on brushing your teeth, visiting a restaurant and crossing the road.
Although aimed at people in the US, the resources are also available to audiences in the UK.
There are around 700,000 people in the UK diagnosed with autism, according to The National Autistic Society.
Mark Lever, the charity’s chief executive, said in a statement to Newsbeat that his organisation hopes it will “inspire” other creators to include characters with autism in their work.
“What we like most about their approach is how it celebrates difference and shows how a little understanding can change everything,” he said.
“For instance, one scene in the Sesame Street storybook shows Julia flapping
“Rather than giving her an unhelpful and judgemental look – as can often happen in reality – Elmo simply explains that this means that Julia is excited.”