ThirdLove is an American lingerie company founded by Heidi Zak and her husband, David Spector, in 2013.

ThirdLove is also known for its online FitFinder quiz, which helps users determine their best fit bra and style.

To generate more interest in the bras, the company streamlined its app and implemented its try-before-you-buy program in March 2015.

Investors included NEA, Andreessen Horowitz, Yuri Milner, Silas Chou, Barry Sternlicht, Munjal Shah, Nasir Jones (NAS), and XG Ventures.

The Series A investment was $8 million in 2016 and investors included New Enterprise Associates and Lori Greely (former CEO of ThirdLove's competitor, Victoria's Secret[21]).

[22][23] On November 18, 2018, Zak condemned Razek's comments and pushed for inclusivity in an open letter in the New York Times that went viral on Instagram.