Supporters will be able to gain entry free on a first-come-first-served basis from 11am, with live music and tournament highlights shown on big screens.
Manager Sarina Wiegman and the team will take to the stage for a Q&A and trophy lift, in an event that is due to be broadcast live on BBC One from 12.40pm. It is expected to end by 2pm.
The FA’s chief executive, Mark Bullingham, said the victory was an “iconic moment for English football” and that the team had “captured the nation’s hearts”.
“It has been an honour to host the tournament in England and the fans have been so important during the team’s journey to success this summer, so it’s only right that they can celebrate this historic victory together at Trafalgar Square,” he said.
The Mayor of London, Sadiq Khan, said he “couldn’t be more proud of the team today – they’ve displayed extraordinary talent and determination throughout the tournament, they’ve broken records, and now they’ve made history.”
He added: “I would like to thank Sarina Wiegman and the Lionesses for treating us to an amazing summer of football.
“I can’t wait to see them lift the trophy again as they celebrate with the fans on Trafalgar Square on Monday.”
Fans will be able to bring their own food and disposable or reusable water bottles on site, with free water refills also available. However, glass bottles will not be allowed.
The Culture Secretary, Nadine Dorries, said: “I’m delighted that we have worked quickly with the FA to put on a victory celebration in Trafalgar Square.
“It will be a fantastic opportunity to thank Sarina Wiegman and the team for all they have achieved.”
The event is being organised in a collaboration between City Hall, the Department for Digital, Culture, Media and Sport, and Westminster City Council.