Thrive Global is described as "corporate and consumer wellbeing and productivity platform".
Huffington revealed her intentions on Twitter today, saying: "I thought HuffPost would be my last act. But I’ve decided to step down as HuffPost’s editor-in-chief to run my new venture, Thrive Global."
She co-founded Huffington Post 11 years ago, and AOL bought the site in 2011 for a reported $315m.
I thought HuffPost would be my last act. But I’ve decided to step down as HuffPost’s editor-in-chief to run my new venture, Thrive Global.— Arianna Huffington (@ariannahuff) August 11, 2016
Huffington said: "When I decided to create Thrive Global, I thought it would be possible to build a startup and continue as editor-in-chief of the Huffington Post.
"Today, it’s clear that was an illusion. As Thrive Global moved from an idea to a reality, with investors, staff, and officer, it became clear to me that I simply couldn’t do justice to both companies.
"Change is desperately needed if another generation is to avoid the burnout that all too often comes with success today.
"That’s why I’m filled with excitement at the prospect of devoting the rest of my life to accelerating the culture shift away from merely surviving and succeeding to thriving."