The former Victoria's Secret model has praised the tennis star - who she sits alongside on the board of Oath, which owns the likes of AOL and Yahoo - for always ''challenging the status quo''.
She told the New York Times newspaper: ''Serena is one of the most extraordinary women on the planet. She challenges the status quo in so many ways, and I learn from her constantly.''
Karlie's comments should come as no surprise as she previously revealed how she believes it is ''important and necessary'' for women to support one another like she has been supported by her sisters, her mother, and her friends throughout her career.
Asked how important she finds the idea of women backing one another, she said: ''It's such an important and necessary thing. I feel really lucky that I've had the guidance of my sisters, my mom, the strong women in my family my whole life.
''But also throughout my career, I've had the support of friends, whether they're my peers or mentors, women older than me who have been incredible friends and advocates. They've really shaped who I've become. It's important to share that kind of friendship and mentorship. It's like this amazing gift that keeps on giving, because when you are that friend or mentor to somebody else, that is a gift that they then want to share.''
The blonde beauty has studied coding and has since launched organisation Kode With Klossy, which arms young women with the tools they need to enter the tech world.
Asked why she decided to learn how to code, she added: ''I wanted to understand the secret language of code and how things worked. Whether it's social media, apps, software, or hardware, to understand how technology built it is fascinating. I also wanted to know if this was something that I could learn. I started Kode With Klossy because as my mind opened to understanding how mighty coding is, I wanted to share that with you.''