Sophia Amoruso is giving up her official #GirlBoss title.

The Nasty Gal founder and author of the book “#GirlBoss,” which details her experience in launching the online fashion retailer, announced Monday that she will be stepping down as chief executive. Amoruso will stay on as executive chairman, leading the company’s creative and brand marketing teams.

President Sheree Waterson will become Nasty Gal’s new chief and has joined the company’s board. Waterson, who previously served as chief product officer of Lululemon, came onboard early last year and oversaw merchandising, design, planning and production, including the opening of its first brick-and-mortar store on Melrose Avenue.

“Sheree brings a wealth of experience in both business and leadership that will help guide us into the next phases of our growth,” Amoruso said in a statement. “In the past 11 months alone, we have already seen the impacts of Sheree’s strategic thinking and approach in our product offering and experience. She has established herself as an inspiring leader here at Nasty Gal and I am confident in her ability to execute on our vision.”

Nasty Gal launched in 2006 out of Amoruso’s personal eBay store, which resold vintage designer pieces. The e-commerce brand quickly grew and eventually released its own clothing, shoe and accessory lines after amassing huge social media followings.

The downtown Los Angeles company posted $100 million-plus in revenue in 2012 but reportedly saw stagnant growth in recent years. Nasty Gal laid off 10 percent of its staff last summer.

Staff reporter Melissah Yang can be reached at [email protected]. Follow her on Twitter @MelissahYang for the latest in L.A. tech news.