Barbie may still have Ken and her Dream House, but she’s struggling to hang onto the one thing she needs most — her fan base.

Toymaker Mattel reported on Thursday that its Barbie brand saw a staggering 21 percent decline in sales during the third quarter compared with the same period last year. This most recent slide comes on the heels of two rough quarters in which Barbie saw sales decrease by at least 14 percent each period.

Barbie is still one of the top doll brands in the world, but girls are increasingly enticed by more innovative dolls such as those from Mattel’s Monster High line and high-tech games that work on a tablet or smartphone.

Mattel executives told investors on a conference call this morning that the company was working to get Barbie back on track.

“We’ve invested in the doll, the dolls look better than last year,” said Bryan Stockton, Mattel’s chief executive. “We have more activities going on in terms of the accessory part of the business.”

For all of its toy brands, including Barbie, Mattel is focusing its marketing and advertising muscle on the crucial fourth quarter, a strategy the company hopes will help it pull in more dollars from holiday shoppers.

The weakness in the Barbie brand was partially offset by strong sales in Mattel’s line of Disney toys, especially those tied to the blockbuster movie “Frozen.”  However, the enormous popularity of these toys is not going to be a tailwind for Mattel much longer.  Disney will be taking the license for its Disney Princess and “Frozen” toys to rival toy maker Hasbro in 2016, a move that means Mattel is going to have to find ways to fill a massive revenue hole.

Mattel also reported that sales in its American Girl brand slipped 7 percent in the quarter.  The company said the number looks comparably unfavorable because last year’s third quarter was an unusually strong, with shoppers rushing to buy the beloved Molly doll before the brand retired it.

Earlier this year, Mattel lost its long-time mantle as the world’s largest toy maker as its rival, Lego, saw rocketing sales amid the success of “The Lego Movie.”

While Mattel will be wounded by the loss of some of its Disney licenses, the toy maker has plenty of other licenses for screen characters that its hopes will help it boost sales.  In the fourth quarter, its Hot Wheels brand will release a line of Star Wars cars.  Mattel also has partnerships with Warner Bros., which just this week announced plans for 10 new films based on DC Comics characters such as Wonder Woman.